Biology subjects

Foxon, F.

Publications and source records attributed to Foxon, F..

4 recordsLinked to original sources

bioRxiv2023

The Moa the Merrier: Resolving When the Dinornithiformes Went Extinct

The Moa (Aves: Dinornithiformes) are an extinct group of the ratite clade from New Zealand. The overkill hypothesis asserts that the first New Zealand settlers hunted the Moa to extinction by 1450 CE, whereas the staggered survival hypothesis allows for Moa survival until after Europeans began to arrive on New Zealand. Alleged Moa sightings post-1450 CE may shed light on these competing hypotheses. A dataset of 97 alleged Moa sightings from circa 1675 CE to 1993 CE was constructed, with sightings given subjective quality ratings corresponding to various statistical probabilities. Cumulative probabilities of Moa persistence were calculated with a conservative survival model using these probabilistic sighting-records; a method recently applied to sightings of the Thylacine. Cumulative persistence probability fell sharply after 1408 CE, and across pessimistic and optimistic variations of the model, it was more likely than not that the Moa were extinct by 1770 CE. Probabilistic sighting-record models favour the overkill hypothesis, and give very low probabilities of Moa persistence around the time of European arrival. Eyewitness data on Moa sightings are amenable to scientific study, and these methods may be applied to similar animals.

zoology↗

bioRxiv2023

If not a fake, what's in the lake?

An animal dubbed Champ has been sighted by hundreds of eyewitnesses in a large, near-oligotrophic lake in North America. A widely-publicised photograph taken by Mansi purportedly depicting the animal was published to much fanfare. In the present study, sightings were coded and analysed using interrupted time-series models, Pearson correlation coefficients, and descriptive statistics. The number of sightings per year was statistically significantly higher after publication of the Mansi photograph compared to before, which may be evidence of expectant attention, or publicity leading to more lake-goers and therefore more animal sightings. Sightings were consistent in condition (mostly Summer, from Noon to Evening, > 1 witness, and a calm lake surface) which may be interpreted as consistency of when lake-goers visit Champlain, or as evidence of consistent behavioural characteristics of Champ animals. Sightings were highly inconsistent in reported Champ characteristics with widely varying morphology, and most sightings were missing morphological data entirely. More than a quarter of sightings were likened to logs, land mammals, birds, fish, and boats, which are all found in the lake. There were no associations between distance to sighting, estimated length, and estimated height of objects witnessed, which may suggest that eyewitnesses provide inaccurate estimates of these measurements in lake settings. If not a fake, whats in the lake may be ordinary phenomena mistaken for Champ. Alternatively, Lake Champlain is inhabited by as-yet undiscovered multi-humped, dark-coloured serpents approximately seven meters in length, which locomote in a fast and sinuous fashion, and which enjoy pleasant Summer evenings and crowds. Deciding which explanation best accounts for the data is left as an exercise for the reader.

zoology↗

bioRxiv2023

If it's there, could it be a bear?

It has been suggested that the American black bear (Ursus americanus) may be responsible for a significant number of purported sightings of an alleged unknown species of hominid in North America. Previous analyses have identified correlation between sasquatch or bigfoot sightings and black bear populations in the Pacific Northwest using ecological niche models and simple models of expected animal sightings. The present study expands the analysis to the entire US and Canada by regressing sasquatch sightings on bear populations in each state/province while adjusting for human population and forest area in a generalized linear model. Sasquatch sightings were statistically significantly associated with bear populations such that, on the average, every 1, 000 bear increase in the bear population is associated with a 4% (95% CI: 1%-7%) increase in sasquatch sightings. Thus, as black bear populations increase, sasquatch sightings are expected to increase also. On the average, across all states and provinces in 2006, after controlling for human population and forest area, there were approximately 5, 000 bears per sasquatch sighting. Based on statistical considerations, it is likely that many supposed sasquatch are really misidentified known forms. If bigfoot is there, it may be a bear.

zoology↗

bioRxiv2023

If it's real, could it be an eel?

Previous studies have estimated the size, mass, and population of hypothetical unknown animals in a large, oligotrophic freshwater loch in Scotland based on biomass and other observational considerations. The eel hypothesis proposes that the anthrozoological phenomenon at Loch Ness can be explained in part by observations of large specimens of European eel (Anguilla anguilla), as these animals are most compatible with morphological, behavioural, and environmental considerations. The present study expands upon the eel hypothesis and related literature by estimating the probability of observing eels at least as large as have been proposed, using catch data from Loch Ness and other freshwater bodies in Europe. Skew normal and generalized extreme value distributions were fitted to eel body length distributions in order to estimate cumulative distribution functions from which probabilities were obtained. The chances of finding a large eel in Loch Ness are around 1 in 50, 000 for a 1-meter specimen, which is reasonable given the lochs fish stock and suggests some sightings of smaller unknown animals may be accounted for by large eels. However, the probability of finding a specimen upwards of 6 meters is essentially zero, therefore eels probably do not account for sightings of larger animals. The existence of exceedingly large eels in the loch is not likely based on purely statistical considerations.

zoology↗