An Higher Palaeolithic Proto-writing System and Phenological Calendar | Cambridge Archaeological Journal

Higher Palaeolithic synthetic/exterior reminiscence methods

It’s usually accepted that common collection of marks on Higher Palaeolithic materials tradition symbolize notational counting, constituting the ‘materials scaffolding’ by which data could be saved outdoors the physique (d’Errico & Cacho Reference d’Errico and Cacho1994; Overmann Reference Overmann2016; Wynn et al. Reference Wynn, Overmann, Coolidge, Janulis, Wynn and Coolidge2016). This may be achieved in a number of methods: from subitization (the flexibility to evaluate the numerosity of small units of things -up to ~4-at a single look), to cardinality (a capability to report the numerosity of the objects in a set by means of counting, aided for numbers as much as 20 by utilizing fingers and toes, and past by internalizing the depend mentally or by externalizing the depend utilizing easy tallies marked on sticks or bone), to ordinality (the flexibility to assign a price based mostly on the sequential place of an merchandise in a set). Cognitively these are distinct expertise with distinct neuronal substrates within the mind (Tang et al. Reference Tang, Ward and Butterworth2008), with subitization being probably the most fundamental and ordinal representations probably the most subtle and going past cardinal representations (youngsters grasp cardinal illustration of numerosity earlier than they perceive ordinal representations: see, e.g., Sasanguie & Vos Reference Sasanguie and Vos2018). For additional dialogue of those points, see the Supplementary Materials.

Marshack (Reference Marshack1991) advised that sequences of traces, dots and cupules on Higher Palaeolithic moveable artwork shaped a part of a counting system with a one-to-one correspondence of indicators to objects, i.e., one line <|> or dot <•> could be the equal of (i.e. symbolize) sooner or later. In his view, particular person traces, dots and cupules represented items of time in numerical type and had been due to this fact counting markers (one line/dot = sooner or later), and sequences of those recorded lunar calendars. To document totally the yearly phases of the moon, he argued, Higher Palaeolithic folks had been in a position to make use of numbers as much as ~377. Whereas the lunar calendar notion didn’t persuade the scholarly group, Marshack’s work paved the best way for the popularity that these units of markings had been synthetic/exterior reminiscence methods, regardless of the purpose for this recording.

Francesco d’Errico has completed a lot to advance our understanding of synthetic/ exterior reminiscence methods. His curiosity has been in the best way that notational objects have been used and the implications of this for human cognitive evolution fairly than decoding the particular data they had been conveying (d’Errico Reference d’Errico and Nowell2002, 38). By means of microscopic traceological evaluation of engraved objects, he has considerably revised the proof for such (e.g. d’Errico Reference d’Errico1989; Reference d’Errico1995a,Reference d’Erricob; d’Errico & Cacho Reference d’Errico and Cacho1994). Most significantly, he has demonstrated that numerical methods had been used all through the Higher Palaeolithic, an analogous time-frame to the African late Center Stone Age (d’Errico et al. Reference d’Errico, Doyon and Colage2017). In his evaluation of the complicated engraved indicators and figurative artwork on an antler retoucher from the Higher Magdalenian of La Marche Cave, he was in a position to display that this constituted an total design, through which a priority to differentiate between teams of markings was prevalent, reflecting the usage of the antler to document distinct classes of knowledge as a man-made/exterior reminiscence system (d’Errico Reference d’Errico1995b; see additionally Marshack & d’Errico Reference Marshack and d’Errico1995).

Within the view of Overmann (Reference Overmann2013; Reference Overmann, Overmann and Coolidge2019), the growing use of numerosity would result in the quantification of time, and that such a quantification must be based mostly on the seasons (see additionally de Smedt & de Cruz Reference de Smedt and de Cruz2011). This level is especially necessary to what follows. The sequences of dots/traces related to animal photographs definitely meet the standards for representing numbers: they’re often organized in registers which can be horizontal relative to the picture with which they seem like related, and are of normal (fairly than random) dimension and spacing, akin to the notion of a Psychological Quantity Line being central to the event of mathematical skills (Brannon Reference Brannon2006; Dehaene et al. Reference Dehaene, Bossini and Giraux1993; Pinel et al. Reference Pinel, Piazza, Le Bihan and Dehaene2004; Previtali et al. Reference Previtali, Rinaldi and Girelli2011; Tang et al. Reference Tang, Ward and Butterworth2008). The surviving sequences range in size; therefore it seems that they used the Additive/Plus One, or Cardinality Precept—every quantity is created by including 1 to the previous quantity, therefore I, II, III … (Corchón Rodriguez Reference Corchón Rodriguez2012; Kelley & Milone Reference Kelley and Milone2005; Marshack Reference Marshack1991; Overmann Reference Overmann2016). For additional dialogue of numerosity, see the Supplementary Materials.

Fritz (Reference Fritz1999) assembled a database of 90 Magdalenian moveable objects from the Dordogne and the Pyrenees, noting appreciable consistency within the ‘principal sorts [of sign] together with linear marks, dashes, angular indicators, arc shapes, damaged traces … dots, numerous influence marks and combos and repetitions thereof’ with no site- or region-specific distinction. She concluded that these had been underpinned by a single conceptual scheme that lacked any important variation in house or time. There’s, due to this fact, little controversy that the usage of sequences of dots, traces and different marks, usually related to animal photographs, mirrored a widespread use of cardinal synthetic/exterior reminiscence methods in Higher Palaeolithic house and time. The precise topic of such methods—the data recorded in them—has been, thus far, elusive.

Higher Palaeolithic prey and predation: the broader context

Higher Palaeolithic hunter-gatherers had been dependent to a big diploma on the acquisition of horse, cervid, bovid, caprid, proboscidean, avian and aquatic meals. In trendy populations, all of those share a attribute annual cycle of mating and birthing seasons separated by spring and autumn migrations of regionally differing extent, with birds and fish outlined extra when it comes to spawning and, due to this fact, presence/absence. Over the annual cycle, populations fission and fuse between smaller and bigger teams, and therefore their distribution in house and time varies significantly however predictably over the course of the yr (e.g. Berger Reference Berger1977; Chaplin Reference Chaplin1977; Clutton-Brock et al. Reference Clutton-Brock, Guinness and Albon1982; Espmark Reference Espmark1964; Goodwin Reference Goodwin1999; Guthrie Reference Guthrie2005; Peck Reference Peck2004; Stiner Reference Stiner1994; White et al. Reference White, Pettitt and Schreve2016).

Zooarchaeological knowledge from Higher Palaeolithic faunal assemblages reveals that related behaviours had been occurring in Pleistocene sources as one would count on, based mostly both on direct equivalents generally or utilizing trendy elephants and rhinos as proxies for mammoths and woolly rhinos respectively (e.g. Delpech Reference Delpech1983; Gordon Reference Gordon1988; Goutas & Lacarrière Reference Goutas, Lacarrière, de las Heras, Lasheras, Arrizabalaga and de la Rasilla2012; Kuntz Reference Kuntz2011; Le Gall Reference Le Gall and Desse1984a,Reference Le Gallb; Reference Le Gall1992; Martin Reference Martin, Bintz and Thévenin1999; Nowak Reference Nowak1991; Rendu Reference Rendu2007). It follows that information of the timing of migrations, mating and birthing could be a central concern to Higher Palaeolithic behaviour, the distribution and timing of which was totally dependent upon these sources (Bocquet-Appel & Demars Reference Bocquet-Appel and Demars2000; Gamble Reference Gamble1986; Van Andel & Davies Reference Van Andel and Davies2003). It’s no shock that excited about animals is central to hunter-gatherers’ being on the planet (Lévi-Strauss Reference Lévi-Strauss1962). Prey animals overwhelmingly dominate Palaeolithic artwork (Bahn Reference Bahn2016; Guthrie Reference Guthrie2005), and pelage, hair, antler development, gregarious and aggressive behaviour and different indications of rutting specifically are generally depicted in some numbers by the Late Higher Palaeolithic, akin to in Lascaux, which could be seen as a fantastic calendar of creation (Aujoulat Reference Aujoulat2005). A lot of its animals are related to indicators: for instance, amongst its row of ‘swimming’ deer stags—often interpreted as an autumn migration scene—one stag is marked with seven pink dots; elsewhere within the cave, in what’s often interpreted as a mating scene with a female and male aurochs in summer season coats, the feminine’s flank is marked with 4 black dots. Later in time at Font de Gaume, two reindeer stags lock antlers—presumably combating within the rutting season—eight dots mark one set of antlers. We’ll return to those particular examples under.

Our speculation

Our curiosity is within the sequences of dots/traces related to depictions of prey animals in Higher Palaeolithic artwork, and within the <Y> signal that seems in a few of these sequences. As we now have famous above, it appears justifiable to imagine that such sequences had been saying one thing concerning the particular taxa with which they had been related, fairly than forming part of the depiction. In the event that they depicted blood or breath, for instance, why would a number of taxa together with aurochs, fish and a cicada be constantly marked with 4 dots/traces in numerous anatomical places (Aujoulat Reference Aujoulat2005; Chollot Reference Chollot1964)? Looking magic, shamanism, different ‘umbrella theories’ and, for that matter, random probability, don’t present a proof for the redundancy of the quantity 4 in lots of photographs (Bahn Reference Bahn, Bahn and Rosenfeld1991, 1–13). As an alternative, we consider that it’s doubtless that this data was numerical in nature, of both a cardinal or ordinal nature.

That we’re searching for number-based data about particular prey animals is due to this fact our level of departure. It appears to us pointless to wish to convey details about the numbers of particular person animals, the occasions they’ve been sighted, or the variety of profitable kills of those; it appears way more doubtless that data pertinent to predicting their migratory actions and intervals of aggregation, i.e. mating and birthing when they’re predicably positioned in some quantity and comparatively susceptible, could be of biggest significance for survival. Given the apparent concern with visible clues to rutting behaviour in artwork mentioned above, we hypothesize that such numerical data ought to document details about the timing of those occasions within the annual spherical.

We’ve seen above that the quantification of issues utilizing psychological quantity traces and the additive/plus one precept, whereby one mark equates/represents one factor, was a attribute of Higher Palaeolithic mark sequences. In our speculation, when related to an animal they need to mark items of calendrical time. On condition that the variety of these is all the time comparatively few, it’s unlikely these symbolize days. We expect it doubtless that the entire variety of marks in a sequence is a method of denoting plenty of months. The obvious items of time for non-agricultural teams are lunar months (de Smedt & de Cruz Reference de Smedt and de Cruz2011; Marshack Reference Marshack1991). The recurrent cycle of the moon’s 4 particular person phases offers a readily seen framework for quantifying time, significantly when assisted by materials scaffolding and, if mandatory, the cycle of ~29 days might be subdivided into 4 subphases of ~7 days (Jègues-Wolkiewiez Reference Jègues-Wolkiewiez2005; Overmann Reference Overmann2013). As not one of the sequences in our database (see under) accommodates greater than 13 marks, they’re in step with the 13 lunar months of a yr. Therefore, we hypothesize that sequences are conveying details about their related animal taxa in items of months. In different phrases, they current ethological data as a seasonal calendar.

If our speculation is right, these synthetic/exterior reminiscence methods would have restricted use except their sequence of months might be anchored to a well-defined begin date, in different phrases, a calendar. Many annual calendars are based mostly on astronomy: for instance, the timing of the equinoxes and solstices. Nevertheless, these are exhausting to watch and, whereas pertinent to the agricultural yr, usually are not related for Palaeolithic hunter-gatherers. The opposite kind of calendar relies on meteorology, significantly the annual temperature cycle. These calendars are immediately related to the cycles of natural world that had been essential for survival within the Pleistocene. Within the absence (we assume) of an in depth photo voltaic system of numbered years, we must be searching for one thing that unambiguously indicators the flip of the yr, i.e, a broadly recognizable occasion with which month quantity one of many yr begins. The plain occasion is the so-called ‘bonne saison’, a French zooarchaeological time period for the time on the finish of winter when rivers unfreeze, the snow melts, and the panorama begins to inexperienced. This after all varies by a number of weeks from the south to the north of Europe, however corresponds roughly to late spring. We hypothesize that spring, due to this fact, with its apparent indicators of the top of winter and corresponding faunal migrations to breeding grounds, would have offered an apparent, if regionally differing, level of origin for the lunar calendar. The issue with lunar calendars is that there are about 12.37 lunar months in a photo voltaic yr. This incompatibility between the lengths of the photo voltaic yr and the lunar month was of nice concern within the classical world, the place difficult methods had been devised to beat this drawback, for instance, utilizing the 19-year cycle of the Moon, however we don’t consider that any of those methods had been believable or mandatory within the Palaeolithic world. We undertake the straightforward resolution that they began counting months at first of the bonne saison and continued till counting grew to become irrelevant in late winter—merely re-starting the depend of months at first of the following bonne saison. An excellent benefit of this calendar is that it’s steady in describing the life-cycles of animals and crops regardless of nice geographical and cultural variations within the European Higher Palaeolithic.

Our speculation, then, is that the variety of traces/dots related to a specific taxon is conveying data when it comes to the variety of lunar months that comply with the start of bonne saison (as we name it, relative to bonne saison or RBS). Therefore three marks (whether or not traces or dots), for instance, would refer to a few months after the beginning of the bonne saison. You will need to be aware that this calendar operates as an interval calendar, the place an occasion akin to mating or beginning is positioned within the calendar when it comes to the variety of lunar months which have elapsed because the onset of bonne saison (the occasion signalling the graduation of the calendar) and never as a hard and fast ‘date’. As we now have famous above, nevertheless, many sequences comprise a <Y> inside them, and we have to perceive the which means of this signal. General, the entire variety of marks in sequences missing a <Y>, these containing a <Y> and the ordinal place of the <Y> ought to, in response to our speculation, symbolize particular occasions from the set ‘mating’, ‘beginning’, ‘spring migration’ and ‘autumn migration’.

What would possibly <Y> symbolize? It is among the mostly depicted indicators in Palaeolithic artwork, and presumably meant one thing. Inside sequences its place varies by taxon, as we will see, therefore it’d denote the worth of a property possessed by every taxon that’s distinct from the cardinality of the sequence as a complete. We assume we now have two associated units of knowledge being recorded right here: the complete quantity of things in a sequence would possibly denote the month through which one necessary occasion happens, and the place of the <Y> inside that sequence which denotes the timing of a second, distinct occasion. Given the set of behaviours of most curiosity to Palaeolithic hunters, we speculation that <Y> refers to birthing: because of the symbolism both one (line) turns into two (traces) or two parted legs. Therefore, we probably have two occasions, one among which is birthing, expressed in lunar months relative to bonne saison.

Testing the speculation

We hypothesize that the variety of traces/dots, or the ordinal place of <Y> symbols, in sequences related to depictions of prey taxa in Higher Palaeolithic artwork, convey details about occasions in these animals’ annual lives necessary to hunter-gatherers, expressed in lunar months RBS, i.e. anchored to the beginning of the bonne saison. That data is prone to mirror birthing, and presumably mating and/or migration of the animals of concern within the area through which the photographs are discovered (or originated).

As a way to check our speculation we compiled as exhaustive a database of sequence/picture associations as we may from the obtainable world literature and net archives, with a view to discover whether or not the variety of markings and the place of <Y> in sequences was random or ordered, and within the latter case whether or not any obvious order correlated with the ethological and zooarchaeological indicators of the timing of birthing, mating and migration by taxon. After omitting any problematic examples (e.g. these with ambiguous numbers of marks or unclear taxonomic identification of related photographs), these totalled 606 sequences with out <Y> and 256 sequences with <Y>, largely from France and Spain, with some examples from additional to the east (Table 1 and Supplementary Materials). Chronologically they span the Early to Late Higher Palaeolithic, with the overwhelming majority of examples within the latter. We respect it is a lengthy span of time, and had been involved why any particular synthetic reminiscence system ought to final for therefore lengthy. Initially, we divided our samples into two: an early and a late set, the previous spanning the Early and Mid Higher Palaeolithic (Aurignacian–Gravettian) and the latter the Solutrean and Magdalenian, and ran our evaluation. This made no distinction to the outcomes, nevertheless, and therefore we mixed the entire dataset for what follows under. For analytical functions we categorised deer and reindeer collectively as ‘cervids’; ibex and chamois as ‘caprids’; all fish (often salmon or trout) as ‘fish’; and all birds collectively as such. The rationale for this was the same timing of migrations, birthing and mating inside every of those teams. The place these differed by species, for instance between bison and aurochs (the latter based mostly on trendy cattle), we saved them separate. Our analytical teams are: aurochs, birds, bison, caprids, cervids, fish, horses, mammoths, rhinos. Due to exceptionally low numbers we exclude snakes and wolverines. We additionally omitted sequences related to obvious human depictions, or photographs through which such had been half, with a view to deal with these individually at a later date. Anecdotally, together with these wouldn’t alter our outcomes. The total databases and explication of those could be discovered within the Supplementary Materials.

Desk 1. Variety of sequences with and with out <Y> in our evaluation, by group.

As a way to evaluate the outcomes with the timing of migration, mating and beginning, we transformed trendy ethological data to month relative to bonne saison (RBS). Therefore, the mating of bison, which often happens round August, would happen in month 3–4 RBS (three to 4 months from the beginning of Could). The comparability of recent and Palaeolithic calendars is clearly approximate, on condition that the beginning of the bonne saison relies on native meteorological occasions such because the melting of river ice, disappearance of snows and greening of the panorama, the primary look of migrating birds, and so on., which can range regionally. The ethological timing of those occasions is proven in Table 2, together with trendy months for easy reference. We summed the entire variety of marks RBS and specific these as graphs: the peaks symbolize probably the most generally occurring variety of marks and therefore, in our speculation, actions of that exact taxon that had been of most curiosity to the customers of the substitute/exterior reminiscence system. By evaluating the timing of those peaks to the seasonal behaviours RBS, we check if any are correlated.

Desk 2. Ethological calendar of mating, birthing and migration by taxa, proven in months and transformed relative to bonne saison (RBS). 1 signifies late Could or early June. As there are 13 phases of the primary part of the lunar month within the calendar yr, we take 13 to symbolize the top of the yr RBS, i.e. roughly April. Therefore when bonne saison arrives the outdated calendar is discarded and occasions recorded anew RBS.

Our predictions are that the peaks within the variety of marks related to every taxon shouldn’t be randomly distributed, however must be clearly patterned; and that sample, when expressed RBS, ought to correspond to necessary occasions within the annual lifecycle of that taxon, notably birthing, mating and/or migration. Because the timing of those occasions differs between every of our analytical teams, the dominant variety of marks also needs to differ between taxa. Lastly, statistics ought to reinforce the truth that any patterning discovered can’t be defined as unintentional.

Evaluation

Figure 3 presents the variety of marks in sequences of traces/dots (as bars) by analytical group (i.e. lengths of sequences), expressed in months relative to bonne saison (the place 1 = late Could/early June) along with suits of twin Gaussian combination fashions illustrating total tendencies in every set of knowledge. It may be seen that, generally, the peaks of the fashions correlate both with mating or birthing seasons, indicated on the graphs by the greyscale bars. That is significantly clear for aurochs, bison, horse and mammoth and fish, seen however much less exact for cervids, and never correlated for caprids. No correlation was noticed between peaks and migrations, and the place it’s potential to differentiate between birthing and mating, the peaks clearly correlate with the latter, as is especially clear for aurochs, bison, horse and mammoth, and once more possible for cervids. The info assist our speculation that the variety of marks in sequences of traces/dots with out <Y> convey details about the birthing, however significantly mating behaviour of every taxon.

Determine 3. The variety of marks in sequences of traces/dots by analytical group (i.e. lengths of sequences), expressed in lunar months relative to bonne saison (the place 1 = late Could/early June). Bars under the graphs symbolize the timing of main occasions within the annual lifecycle of the taxa based mostly on trendy ethological parallels. As a way to illustrate the peaks of the distribution of frequencies, we fitted twin Gaussian combination fashions to every set of knowledge (strong line; if the twin Gaussian match didn’t converge we fitted a single Gaussian as an alternative) along with the frequencies noticed (open bars) for every variety of marks in a sequence of dots or traces for every lunar month of the yr.

Figure 4 presents the place of <Y> in sequences, by analytical taxa. To find out the place of <Y>, we assumed that sequences had been oriented in the identical approach as their related animal depictions, i.e. with the animal the proper approach up. Generally there’s a placing correlation between the height place of <Y> within the fashions and birthing for every taxon. The info assist our speculation that the place of <Y> in sequences of traces/dots conveys data, on this case about birthing. That is significantly fascinating, on condition that the variety of traces/dots in sequences with no <Y> signal is indicative of mating.

Determine 4. The place of <Y> in sequences, by analytical taxa. Bars under the graphs symbolize the timing of main occasions within the annual lifecycle of the taxa based mostly on trendy ethological parallels. As a way to illustrate the peaks of the distribution of frequencies, we fitted twin Gaussian combination fashions to every set of knowledge (strong line; if the twin Gaussian match didn’t converge we fitted a single Gaussian as an alternative) along with the frequencies noticed (open bars) for every <Y> place inside a sequence for every lunar month of the yr.

Figure 5 presents the variety of marks in sequences which do comprise <Y>. As soon as once more there’s a clear correlation, on this case with birthing, or each birthing and mating. Two analytical teams stand out from the others in that they don’t seem to be terrestrial herbivores and from the standpoint of Palaeolithic hunter-gatherers could be skilled extra as an look and disappearance as migrations take them into and out of particular areas.

Determine 5. The variety of marks in sequences which comprise <Y>. Bars under the graphs symbolize the timing of main occasions within the annual lifecycle of the taxa based mostly on trendy ethological parallels. As a way to illustrate the peaks of the distribution of frequencies, we fitted twin Gaussian combination fashions to every set of knowledge (strong line; if the twin Gaussian match didn’t converge we fitted a single Gaussian as an alternative) along with the frequencies noticed (open bars) for every variety of marks in a sequence containing <Y> symbols for every lunar month of the yr.

For birds, the place of <Y> correlates with mating and hatching, as does the variety of marks in sequences with <Y>. It appears pretty clear that the priority with sequences related to birds was to convey the supply of eggs. For fish, the variety of marks in sequences with and with out <Y> correlates markedly with the spring migration and hatching.

General, there’s a exceptional diploma of correlation between the numbers of traces/dots in sequences with and with out <Y> and the place of <Y> and the mating and birthing behaviours of our analytical taxa. Our knowledge don’t clarify every part, however even taking imprecision and regional variability under consideration the diploma of assist for our speculation is placing. We now discover our outcomes statistically.

Statistical evaluation

Our knowledge encompass information for every taxonomic group for every month of the yr. The months of the yr through which species interact specifically forms of behaviour (mating, giving beginning, or migration in spring and autumn) are all expressed as binary variables (for instance, Aurochs give beginning in month 2, so the ‘beginning’ variable for Aurochs: Month 2 has a price 1, however has a price of 0 in all different months). As well as, we now have variables indicating the variety of occasions we observe numbers or ordinal positions of marks related to that species which correspond to the numerical worth of that month. So, for Aurochs: Month 2 we now have variables that point out the variety of occasions we observe sequences of two dots or traces (1), the variety of occasions we observe a <Y> image in place 2 of a <Y>-containing sequence (13), and the variety of occasions we observe <Y> containing sequences of size 2 (10). We needed to check how nicely the frequencies of marks akin to totally different months predict the prevalence of every kind of behaviour. When predicting an final result that may solely tackle binary outcomes, the suitable check is logistic regression. We performed these analyses utilizing the statistical package deal R (R Core Workforce 2022) utilizing the process ‘glm’ with a logit binomial household hyperlink operate. We performed separate easy logistic regressions, testing how nicely every measure of marks (ordinal place of the <Y> image in a sequence, variety of dots or traces in a sequence with no <Y>, and complete variety of marks in a sequence with a <Y>) predicts every kind of behaviour. When two measures of marks are each good predictors of a behaviour (as we count on would possibly happen for place of <Y> and complete variety of marks in <Y> sequences, which can virtually inevitably correlate with each other) we examined how nicely a mannequin containing each predictors suits the result after which examined whether or not the development gained by including the second predictor is statistically important utilizing the ANOVA process with a chi-squared mannequin comparability check. You will need to confirm that the info being assessed by a statistical check conforms to the mathematical assumptions underlying that check. For easy and a number of logistic regression, we used the R package deal ‘DHARMa’ (Hartig Reference Hartig2022) to check deviation, dispersion and prevalence of outliers previous to logistic regression (none of our knowledge violates these assumptions).

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The outcomes of those analyses are summarized in Tables 3–5 (and see the Supplementary Materials for additional particulars on our statistics).

Desk 3. Easy logistic regression outcomes.

Desk 4. A number of logistic regression outcomes.

Desk 5. Mannequin comparability outcomes.

The primary key message is that the beginning intervals are considerably nicely predicted by the place of <Y> (p < 0.0146). Though the size of <Y> sequences additionally predicts beginning intervals in a easy regression, our a number of logistic regression reveals that when mixed with <Y> place the size of sequence will not be a dependable predictor of beginning interval and, together, is negatively correlated with beginning month. Including size of <Y> sequence to <Y> place doesn’t considerably enhance prediction of beginning intervals (chi-square(1) = 2.451, p >0.05).

Our second key discovering is that mating intervals are considerably nicely predicted by size of sequences of dots or traces not containing a <Y> (p = 0.00236). The variety of marks in a <Y> sequence can be a predictor, however is way much less dependable, solely simply reaching statistical significance (p = 0.0477). In a a number of logistic regression, the variety of marks in a <Y> sequence fails to foretell mating interval (p = 0.878) whereas variety of dots and contours continues to be extremely dependable (p = 0.00558). Including the variety of marks in a <Y> sequence doesn’t considerably enhance prediction of mating intervals (chi-square(1) = 2.451, p >0.05).

We discovered no statistically important predictors of both Spring or Autumn migration intervals.

One query which can strike the reader is whether or not assist for our speculation all depends upon a single outlier group—fish. For instance, of all of the species for which we now have knowledge, the month through which salmon spawn is clearly distinct at 6, whereas all the opposite species have typical months of parturition between 1 and three. We due to this fact performed extra analyses excluding fish from the dataset. There have been no significant variations within the outcomes of analyses with or with out fish. These analyses, along with some extra statistical particulars, are introduced within the Supplementary Materials.