This is unusual for reptiles , because their skin is thick and scaly . Experiments with the black-and-yellow sea snake , Pelamis platurus ( a pelagic species ) , have shown that this species can satisfy about 20 % of its oxygen requirements in this manner , which allows for prolonged dives . This is unusual for reptiles , because their skin is thick and scaly , but experiments with the black-and-yellow sea snake , Pelamis platurus ( a pelagic species ) , have shown that this species can satisfy about 20 % of its oxygen requirements in this manner , which allows for prolonged dives .