Nearly a fifth of reptiles face risk of extinction: Study

According to a new report, nearly a fifth of all reptile species globally are at risk of extinction.

Key findings of the Report:

The report analysed 10,196 reptile species following the same criteria as the IUCN’s Red List of Threatened Species.
It found at least 1,829 are threatened.
Around 30 per cent of forest-dwelling reptiles are at risk of extinction, compared with 14 per cent of reptiles in arid habitats.
Threatened reptile species are concentrated in South-eastern Asia, West Africa, northern Madagascar, the northern Andes and the Caribbean.
Some parts of southern Asia and north-eastern United States have twice the number of reptile species in a threatened category than other tetrapods.
South-eastern Asia, India, West Africa and the Caribbean comprise the top 15 per cent areas of phylogenetic (reconstructing the past evolutionary history of existing/surviving species) diversity loss, with high concentrations of threatened and evolutionarily distinct species.
Around 15.6 billion years of evolutionary history will be lost from the face of the earth if these 21 per cent species of reptiles go extinct in the coming years.

The Study

Major threats for the reptile species

Reptiles are threatened by the same major factors that threaten other tetrapods (a superclass of animals that includes all limbed vertebrates):
Agriculture
Logging
urban development and
invasive species
Although, the threat posed by climate change remains uncertain.
Many threatened species of reptiles are concentrated in places where other vertebrates are also threatened.
The proportion of turtles and crocodiles that are threatened (57.9% and 50.0%, respectively) is much higher than those of squamates (19.6%) and tuatara (0%), and comparable to the most-threatened tetrapod groups, salamanders (57.0%) and monotremes (60.0%).
The Galapagos marine iguana, the world’s only lizard adapted to marine life, is classified as “vulnerable” to extinction.
- It took 5 million years for the lizard to adapt to foraging in the sea, lamenting “how much evolutionary history can be lost if this single species” goes extinct.

Reptiles:

Reptiles are a class of vertebrates made up mostly of snakes, turtles, lizards, and crocodilians.
These animals are most easily recognized by their dry, scaly skin. Almost all reptiles are cold-blooded and most lay eggs—though some, like the boa constrictor, give birth to live young.
Instead of possessing gills like fish or amphibians, reptiles have lungs for breathing.
Unlike birds and mammals, reptiles do not maintain a constant internal body temperature.
Without fur or feathers for insulation, they cannot stay warm on a cold day, and without sweat glands or the ability to pant, they cannot cool off on a hot one.
- Instead, they move into the sun or into the shade as needed. During cooler parts of the year they become inactive.
- Because of their slow metabolism and heat-seeking behavior, reptiles are cold-blooded.
Reptile reproduction also depends on temperature.
- Only boas and pythons give birth to live young.
- The other species lay their eggs in a simple nest, and leave.
- The young hatch days to months later.
The soil temperature is critical during this time: It determines how many hatchlings will be male or female. Young reptiles can glide, walk, and swim within hours of birth.
Reptiles first appear in the fossil record 315 million years ago and were the dominant animals during the Mesozoic era, which lasted for 270 million years until the extinction of the dinosaurs.