February 21, 2025
Dolphins with Style: Introducing the Spotted & Hourglass Dolphins
BY: Maya Lozinsky
Did you know that nearly 40 different dolphin species swim in oceans and rivers all around the world? While all dolphins are known for their social, playful, and intelligent nature, their appearances and habitats can be surprisingly diverse.
Let’s take a closer look at two remarkable species: the pantropical spotted dolphin (Stenella attenuate), a freckled tropical speedster, and the hourglass dolphin (Lagenorhynchus cruciger), a bold black-and-white resident of the Southern Ocean.
APPEARANCE
The hourglass dolphin is named after the striking white pattern along its sides, which resembles an hourglass. This species uses countershading — a form of camouflage — to evade predators. Its lighter belly blends with the bright ocean surface when seen from below, while its darker back helps it disappear into the deep waters when viewed from above.
While the hourglass dolphin stands out with its striking contrast, the pantropical spotted dolphin has a more subtle appearance. Despite its name, this species isn’t born with its signature spots—these develop gradually, eventually covering its body by adulthood. Another distinguishing trait is its white “lips” or snout.
HABITAT
Although dolphins can travel great distances, they tend to stay within habitats that best suit their needs. Hourglass dolphins thrive in the icy, open waters of the Southern Ocean, navigating the seas surrounding Antarctica.
Pantropical spotted dolphins, on the other hand, have a more expansive habitat, inhabiting and traversing and subtropical oceans all across the world. As their name suggests, they prefer warmer waters and are even occasionally seen near coastlines. Some migrate seasonally to Japan, while most are found between the equator and the Galápagos Islands.
BEHAVIOR
Both pantropical spotted dolphins and hourglass dolphins are highly social and often travel in groups. Hourglass dolphin pods can range in size from just a few individuals to around 100, while pantropical spotted dolphins form much larger pods, sometimes numbering in the thousands.
Like most dolphins, hourglass dolphins are curious and playful. They have been observed altering their swimming patterns to interact with boats, often riding the bow waves of larger vessels and even surfing the wakes of big whales.
Pantropical spotted dolphins are exceptionally fast, reaching speeds of up to 17 miles per hour (about 27 kilometers per hour). Their agility and speed allow them to leap impressively high out of the water.
THREATS
Both pantropical spotted and hourglass dolphins are classified as species of Least Concern by the IUCN.
Hourglass dolphins face relatively few threats due to their remote habitat and are very rarely victims of bycatch.
However, bycatch was once a significant threat to the pantropical spotted dolphin population. These dolphins are frequently spotted swimming alongside yellowfin tuna. As a result, many fishers intentionally used the presence of spotted dolphins to locate tuna schools and caught dolphins in the process. This practice became so popular that an estimated 550,000 dolphins died as a result of fishing bycatch in 1961. Since then, regulations have been put in place to help reduce mortalities of this species, although dolphins are still sometimes caught as collateral.
GET INVOLVED
Although these species are not currently under threat, it’s up to us to keep it that way. Learn more about these creatures on Oceana’s Marine Life Encyclopedia, or by learning about how Oceana protects these dolphins’ habitats.