Contrary to popular myth, there is no official term for the offspring of echidnas. The term "puggle" has reportedly been used in Australian bush lore as a name for baby echidnas for many decades. There have been claims that it developed as a name for baby echidnas, as they resembled "Puggles", an American soft-toy character. Perhaps because echidnas and platypuses are both monotremes, the term began to be applied to young platypus as well.
The company producing the "Puggles" toy considered legal action against the unauthorised use of the term "puggles". Whether or not this action went ahead is undetermined, and some have alleged that it could be illegal to use the word for anything other than the soft toy.
Kangaroos do not lay eggs. They are marsupials, not monotremes, and therefore are not egg-laying mammals like platypuses and echidnas. Their offspring are born live.
Echidnas do not hibernate.
No. Echidnas do not hop. They walk.
There are no echidnas in Bali. Echidnas are found only in Australia and on the island of New Guinea.
No. All echidnas are mammals, and all mammals are vertebrates. Echidnas are different from "echinoderms".
No. Echidnas eat termites.
Yes. Echidnas are solitary animals.
Echidnas do not hibernate.
Echidnas do not hibernate.
No. Echidnas are not hostile to people or other animals.
There's no collective term for a group of echidnas.
Yes. Echidnas are vertebrates. They are mammals, and all mammals are vertebrates.