Use is_same
:
#include <type_traits>
template <typename T>
void foo()
{
if (std::is_same<T, animal>::value) { /* ... */ } // optimizable...
}
Usually, that's a totally unworkable design, though, and you really want to specialize:
template <typename T> void foo() { /* generic implementation */ }
template <> void foo<animal>() { /* specific for T = animal */ }
Note also that it's unusual to have function templates with explicit (non-deduced) arguments. It's not unheard of, but often there are better approaches.