One way to tell a sea lion from a seal is that a sea lion has ear-flaps whereas a seal does not. Here are some more distinguishing features:
Sea lions have no distinguishable nails on their front flippers, whereas seals have claw-like nails.
Seals have nails on all digits of their hind flippers, but sea lions have nails only on the middle three digits.
Sea lions' flippers are usually hairless, unlike those of seals.
The front flippers of a sea lion are long and wing-like; the front flippers of a seal are short and blunt.
The Chinese used to use sea lion whiskers to clean opium pipes.
Sea lions are unable to see the colour red, which they cannot distinguish from grey.
Sea lions can suffer from epilepsy.
Research published in 2004 showed that a sea lion could remember things it has learned 10 years previously, the longest memory interval ever recorded in a non-human mammal.
'Sea lions' is an anagram of 'a lioness'. 'Pigeon' is an anagram of 'one pig'.