Hello readers,

Yesterday a lot of species were sighted. We saw the friendly Common Dolphin (Delphinus delphis), the dynamic and gorgeous Atlantic Spotted Dolphin (Stenella frontalis), the amazing and impressive Sperm Whale (Physeter macrocephalus), the jumpy and acrobatic Striped Dolphin (Stenella coeruleoalba) and finally the peculiar looking but beautiful Risso’s Dolphin (Grampo griseus).

Striped dolphin / Stenella coeruleoalba porpoising (picture from our archive).


As the Risso’s Dolphins are not that commonly known from the public we will talk a bit more about them.

They are one of our resident species, which means that they can be sighted all year round in the Azores and with peak sightings season going from April to October. They have a rounded head without a beak. Also, as a result of playing and fighting, juveniles and adults can simply be identified by the white scars covering their greyish bodies. For younger animals it can be a bit more tricky as they are mostly completely grey, but most of the time they will be accompanied by adults. This white pattern makes them really beautiful to look at, almost giving us the impression of seeing ghosts calmly travelling at the sea surface.

Risso’s Dolphin juvenile / Grampus griseus back breaching


Risso’s Dolphins are known to be deep divers and can stay underwater for around 30 minutes before coming back at the surface to breath. Sometimes flukes raising can be seen previous to a deep dive. During foraging, confrontations with squids can also provide some additionnal scarring to the body.

The scars on each animal are unique and pictures of the marked dorsal fin can be used for photo-identification. If you are interested in Photo-ID, you might want to check out the platform MONICET http://www.monicet.net/en

Now you know a bit more about this mistic species that we love to encounter during our tours.

Stay curious about all the wonderful things surrounding us.

Aurora Crucianelli

About Aurora Crucianelli

Aurora Crucianelli is an Environmental Biologist with a Master’s degree in Oceanography. She loves the sea and likes to scuba dive during her spare time. She also worked as a science teacher and enjoys educating people and share her passion for the ocean and wildlife.

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