Dolphins Home

What are dolphins?
Dolphins, like you and me, are mammals. They have teeth, are warm-blooded, have a four-chambered heart, and nurse their young from mammary glands. Dolphins also have hair — but not very much!

Whales Dolphins belong to a group of mammals called cetaceans. Cetaceans include all whales and dolphins. Some cetaceans, like the blue whale, are baleen whales and have horny plates hanging from their upper jaw that are used to strain food from the ocean. Others, like dolphins, are "toothed whales."

In the group of toothed whales, there are several subgroups:


oceanic dolphins 32 species
river dolphins 5 species
sperm whales 3 species
beaked whales 19 species
beluga and narwhal 2 species
porpoises 6 species

The dolphins that we are studying in the Indian River Lagoon are bottlenose dolphins and they belong in the subgroup of oceanic dolphins.

What's the difference between a dolphin and a porpoise?
Even though they are both toothed whales, they have different body shapes. Dolphins usually have a large forehead. The easiest way to tell them apart is to look at their teeth. All dolphin teeth are round when you cut them in half. All porpoise teeth are flat.

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