between 8.5 – 13 ft.
up to 660 – 1,100 lbs
around the US contintental shelf, 60,000; in the eastern tropical waters, 175,000; in the west, 85,000.
Where do Risso’s dolphins live? In many places! They can be found worldwide in tropical, subtropical, and temperate oceans. They prefer deeper waters but also inhabit coastal areas.
Risso’s dolphins are also sometimes called gray dolphins. As well, they have been considered to be a part of the subfamily, “blackfish.” This family includes false killer whales, pygmy killer whales, melon-headed whales, long finned pilot whales, and short-finned pilot whales. Their bodies are very robust with narrow tails. Their bulbous heads have no distinguishable beak and their tall, curved dorsal fin can be found halfway down their backs. Calves are darker in color while the adults coloring starts to fade to a pale gray.
Unlike their calves, Risso’s dolphin adults have heavy scarring. Why do Risso’s dolphins have scars? Simply due to other dolphins teeth scraping against them as well as marks from their prey. They have a low number of teeth, with only up to seven pairs in their lower jaw. They use these to capture their prey, consisting of fish, krill, and cephalopods. Some more Risso’s dolphins facts are that they can be found in groups of up to 30 or traveling independently. They have been reported to associate with other dolphins, such as bottlenose and pacific white-sided dolphins. Risso’s dolphins have an estimated lifespan of 35 years.