whelp
A baby dog or other young wild animal.
A whelp is a puppy or the baby of certain animals like wolves, lions, tigers, or seals. When a dog gives birth, her whelps are those tiny, squeaking puppies that can barely open their eyes. A lioness nursing her whelps in the tall grass is caring for her cubs.
The word sounds a bit old-fashioned because people usually say “puppy” or “cub” these days, but you'll find whelp in classic stories and nature writing. White Fang, Jack London's famous novel about a wolf-dog, uses the word throughout to describe the young wolves.
Interestingly, whelp can also mean to give birth to these young animals. A wolf whelps when she has her pups. You might read that “the she-wolf whelped in early spring.”
Sometimes people use whelp as a mild insult, calling someone an impudent or annoying young person, though this usage is rare and sounds deliberately old-timey, like something a grumpy character in a medieval story might say.