Why do Risso’s dolphins have scratches?

Answered by James Kissner

Risso’s dolphins, also known as gray dolphins, are known for their distinctive appearance and the scratches on their bodies. These scratches are believed to be a result of various behaviors and activities that they engage in.

One possible reason for the scratches is rough play and social interactions among the dolphins. Like many other dolphin species, Risso’s dolphins are highly social animals and often engage in playful behaviors with each other. This can include chasing, wrestling, and even biting each other. These interactions can sometimes get rough, leading to the dolphins getting scratched or marked on their bodies.

Another reason for the scratches is their hunting behavior. Risso’s dolphins primarily feed on squid and other cephalopods, which they catch by diving deep into the ocean. During these dives, they may encounter sharp objects such as the beaks of squids or other underwater debris. These encounters can result in scratches and scars on their bodies.

Additionally, Risso’s dolphins have been observed engaging in a behavior known as “head-slapping” or “tail-slapping.” This behavior involves the dolphin leaping out of the water and forcefully slapping its head or tail on the surface. While the exact purpose of this behavior is not fully understood, it is believed to be a form of communication or a way to stun prey. The forceful impact with the water surface can cause scratches and abrasions on their bodies.

It is also worth noting that the scratches on Risso’s dolphins can provide valuable information about their life history and behavior. Marine biologists and researchers often use these markings to identify and track individual dolphins. By cataloging and studying these markings, scientists can gain insights into the movements, social interactions, and health of these dolphins.

The scratches on Risso’s dolphins are likely a result of various behaviors such as rough play, hunting encounters, and surface slapping. These scratches not only add to the distinct appearance of the dolphins but also provide valuable information for scientific study.