Two types of pilot whales

There are 2 types of pilot whale: the long-fin pilot whales usually reside in colder northern waters such as Norway, Iceland or Canada and there is also a population in the Mediterranean; while the short-fin pilot whales prefer warmer waters, such as the Canary Islands. In the Azores, we can see both types. Over the past few years, long-fin pilot whales have been observed in the spring or early summer while the short-fin are present throughout the summer and have been recorded in the Azores for many years.

How to tell them apart – it isn’t easy!

There are a few differences between the two species. The main one (although we can’t see it from the surface) is the length of the pectoral fin. In the long-fin, the pectoral fin is around 1/4 of the body length, while the short-fin has shorter flippers only up to about 1/6 of the body length.

Short-fin pilot whales have more color variation on the top of their bodies, with lighter shading on the “shoulders” and down the back in comparison to the long-fin; but the short-fin have less pigmentation on the underside; another feature that we can’t see from the surface. The long-fin pilot whales have a very visible “anchor patch” on their chest, which is not as defined on the short-fin.

Long-finned pilot whales are slightly larger, with males reaching lengths between 4-6.7 meters and females 3.8-5.7m, while most short-finned pilot whales are a bit smaller; males typically measuring around 4.2-7.3m and females 3.2-5.1m. Long-finned pilot whales also possess a more pronounced dorsal fin, sloping further towards the back, compared to the shorter and more rounded dorsal fin of their short-finned counterpart.

Differences in behavior

From the few encounters that we have had with the long-fin pilot whales, there are some big differences in the behavior of the 2 species. The long-fin we have “met” tend to show some curiosity about the boat and come over to inspect us, sometimes almost appearing to bowride like their smaller dolphin cousins. We have observed them breaching out of the water as well as spy-hopping which is when they lift their head, up to the eye, out of the water. Both of these 2 behaviors allow us to see the pigmentation pattern on the chest of the animals, which helps to confirm the species. In the Azores, the short-fin do not usually approach the boat and we (the author) have never seen one breach out of the water (yet).

We have certainly been enjoying the sightings of the long fin pilot whales over the last month, but most likely for the rest of the summer to come, it will be the usual short-fin pilot whales that we see. Whichever species it is, seeing these large, deep diving dolphins is always a treat.