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The answer depends on what you want tell it apart from!
Cats have retractable claws, a unique feature that sets them apart from other animals.
it depends what you are telling apart
they haven't
Cats' paws have sharp, retractable claws, while dogs have hard, dull claws that don't retract.
it sucks apart from horse riding and my cats and my mates and 2 of my cats and our dog died
Fish
Yes, cats have the ability to remember their owners even after a year of being apart. They may exhibit signs of recognition and familiarity when reunited with their owner.
Meerkats tell each other apart with smell and dominant
Depends what "them" is
As humans we have a hard time telling penguins apart. However, They can tell each other apart by distinct vocalizations.
For the average human viewer there appears to be little way to tell a Pill Bug apart but they do have markings on there backs which can allow them to be told apart.