A popular pet, but an invasive species
The red-eared slider (Trachemys scripta elegans), also known as the red-eared terrapin, is a semiaquatic turtle belonging to the family Emydidae.
This turtle is very cute when young and this makes it a popular pet, but many are released into the wild as they grow. It is native to the southern United States and northern Mexico, but it is now firmly established in Hong Kong where it outcompetes native species.
When temperatures drop below 10degrees the animals goes into a state of "Sopor", which is defined as a condition of abnormally deep sleep or a stupor from which it is difficult to rouse. This is a form of hibernation. Sunny spells wake them again.