Papers by Colin Stevenson
Journal of Threatened Taxa, 2021
This study quantifies the morphometric relationship between total length (TL) and head length (H... more This study quantifies the morphometric relationship between total length (TL) and head length (HL) for a sample of 53 Mugger crocodiles (43–280 cm TL) in Iran. Across the size range of crocodiles sampled, the relationship was best described by a linear regression (TL= 15.52 + 6.283HL). The average TL/HL ratio was 7.034, which is similar to that reported for other crocodilian species and confirms its usefulness for estimating TL based on HL during population surveys.
Bookmarks Related papers MentionsView impact
CSG Action Plan: Availability of survey data: Poor (but suffi cient to initiate conservation effo... more CSG Action Plan: Availability of survey data: Poor (but suffi cient to initiate conservation efforts in some areas) Need for wild population recovery: Highest Potential for sustainable management: Moderate 2009 IUCN Red List: EN (Endangered. Criteria: C1: Population estimate is less than 2500 mature individuals, with continuing decline of at least 25% within 5 years or two generations. Widespread, but in low numbers; IUCN 2009). It is likely that criteria A1(c): “a decline in the area of occupancy, extent of occurrence and/or decline in habitat” also applies, as habitat loss is the key threat to the species. (Last assessed in 2000).
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Biological Journal of the Linnean Society, 2020
Relationships between distribution patterns and body size have been documented in many endothermi... more Relationships between distribution patterns and body size have been documented in many endothermic taxa. However, the evidence for these trends in ectotherms generally is equivocal, and there have been no studies of effects in crocodylians specifically. Here, we examine the relationship between latitudinal distribution and body mass in 20 extant species of crocodylians, as well as the relationships between seven important reproductive variables. Using phylogenetically independent contrasts to inform generalized linear models, we provide the first evidence of a latitudinal effect on adult female body mass in crocodylians. In addition, we explore the relationships between reproductive variables including egg mass, hatchling mass and clutch size. We report no correlation between egg mass and clutch size, upholding previously reported within-species trends. We also find no evidence of a correlation between measures of latitudinal range and incubation temperature, contrasting with the tr...
Bookmarks Related papers MentionsView impact
Animal Cognition, 2021
Behavioral predispositions are innate tendencies of animals to behave in a given way without the ... more Behavioral predispositions are innate tendencies of animals to behave in a given way without the input of learning. They increase survival chances and, due to environmental and ecological challenges, may vary substantially even between closely related taxa. These differences are likely to be especially pronounced in long-lived species like crocodilians. This order is particularly relevant for comparative cognition due to its phylogenetic proximity to birds. Here we compared early life behavioral predispositions in two Alligatoridae species. We exposed American alligator and spectacled caiman hatchlings to three different novel situations: a novel object, a novel environment that was open and a novel environment with a shelter. This was then repeated a week later. During exposure to the novel environments, alligators moved around more and explored a larger range of the arena than the caimans. When exposed to the novel object, the alligators reduced the mean distance to the novel obje...
Bookmarks Related papers MentionsView impact
Journal of Threatened Taxa, 2017
Human-Crocodile conflict (HCC) occurs to varying degrees around the World, and with a number of c... more Human-Crocodile conflict (HCC) occurs to varying degrees around the World, and with a number of crocodilian species (CrocBITE 2013). The Mugger or Marsh Crocodile Crocodylus palustris found in Gujarat State is the crocodilian species responsible for conflict with local people. This paper is a compilation of HCC occurring in various parts of Gujarat from 1960 to 2013. A total of 64 crocodile attacks were recorded: 44 (24 fatal & 20 non-fatal) on males, and 20 (9 fatal & 11 non-fatal) on females. By region 52 HCC were recorded in central Gujarat; five in Saurashtra, four in the northern region and three in Kutch; no crocodile attacks were recorded in southern Gujarat. Of the two major river systems in central Gujarat, 41 attacks occurred within the Vishwamitri-Dhadhar River System and 11 in the Narmada system. Most crocodile attacks happened between the months of April and September, peaking in May with 14 attacks. These months are the peak breeding season for the species in G...
Bookmarks Related papers MentionsView impact
PLoS ONE, 2013
Bookmarks Related papers MentionsView impact
iucncsg.org
Bookmarks Related papers MentionsView impact
Uploads
Papers by Colin Stevenson