Sharks live in all oceans, for much more that 400,000,000 years, that is to say, from the early Silurian period of Paleozoic era!
In the Arctic ocean greenland sharks (Somniosus microcephalus) are present and prosperous; in the subantarctic waters the large southern sleeper shark (Somniosus antarcticus) is common, even feeding on colossal squids (Mesonychoteuthis hamiltoni).
Between these two geografic extremes, sharks live in all oceans and some species even live in fresh water. They can live in surface as well as abissal waters; perhaps even in the still very poorly explored Pacific deep-sea trenches, unknown shark species may thrive.
There are more than 470 different extant species, some very strange and puzzling, like the rare goblin shark (Mitsukurina owstoni) and the deep-sea megamouth (Megachasma pelagios), hammerheads, all species of the saw shark genus, etc.
yes beceause sharks can move from zone to zone
small
in warm water
yes
The hammerhead shark has to live in big groups of them, you would usually find them in the Australian seas at the bottom floating around waiting to kill their pray.
nope
The Hammerhead Shark Is The Only Endangered Shark In Europe Known
whale
no they lay eggs
The sense that a hammerhead shark uses is their smell.
From my understanding roughly 25 years.
The Hammerhead shark is not a mammal.