Almost all animals that hibernate prepare to do so by eating large amounts of food,which they convert to fat.
Among birds that forage in tree trunks, nuthatches are the only ones that regularly feed with their heads facing downward.
Why is the usage of 'that' in the following sentences correct. These involve plural sentences and shouldn't 'which' be used instead.
Also if there is any rule which differentiates the usage of 'that' for humans and animals, please do post that too.
PS : I've generally seen that used in singular sentences while those used in plural. Any examples involving the contrary would be deeply appreciated.