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Table of Contents
Reptiles
Thermal sex determination
In turtles, alligators, some lizards, and some fish, thermal sex determination occurs; that is, the sex of the young depends on the temperature at which the eggs developed. Higher temperatures induce females, while lower temperatures cause only males to hatch; intermediate temperatures cause individuals of both sexes to be born. These animals do not, like most vertebrates, have sex chromosomes; instead, genes responsible for sex are present in all individuals but are activated or not depending on temperature. 1)
Mysterious dinner snake
A mysterious dinner snake (Cenaspis aenigma) was found in the belly of another snake that was killed by a fruit harvester in the Mexican state of Chiapas. Until the description of the holotype from a partially digested male specimen in 2018, no other specimens of this species had been found, either alive or in museum collections despite numerous expeditions organized to the site where the first specimen was found. Features have been detected, distinguishing it from all known representatives of snakes so far. 2)
Four snakes
The flag and coat of arms of Martinique each feature four snakes. The snake in the coat of arms - the lanceolate broom, caixa - is the only venomous snake found on Martinique and St. Lucia. On the islands (also Trinidad and Tobago), it was artificially acclimated by planters so that its presence in the bush and jungle would deter slaves from fleeing the plantations. Caixa venom contains reteplase, used in laboratory diagnostics to assess the timing of the batroxobin (plasma coagulation) clotting system. 3)
Bothrops
All Bothrops have one thing in common - they have cavities on each side of their heads under their eyes that look like large nasal openings. The thin membrane that lines the bottom of the cavities is dotted with receptors (numbering between 500-1500 per mm²) that can register small temperature differences. 4)
Deep dives
Leatherback turtles are some of the deepest diving marine animals, with recorded encounters at depths of 3000 ft. Due to the pressure there, such depths are unattainable for turtles with hard shells that would be crushed. 5)