‘Cetacean’ is the collective name for all whales, dolphins and porpoise which form the taxonomic order of Cetacea. Despite spending the entirety of their lives in the water, they are mammals like us. Meaning that they are warm blooded, give birth to live young, nurse their young, have traces of hair, and must come to the surface to breathe air through their lungs.

Humans can still breathe while we are asleep, as our respiratory system is involuntary. However, cetaceans have a voluntary respiratory system and have to consciously decide to surface to breathe. Bottlenose dolphins are believed to shut down half of their brain while ‘sleeping’, along with the opposite eye. The other half stays awake at a low level of alertness, to watch for predators, obstacles and also to signal when to surface to breathe. After a period of time this process will be reversed, resting the active side of the brain and waking the rested half. Other mechanisms help cetaceans to hold their breath longer before needing to surface to breathe. Their lungs are proportionally larger than humans, so they can take in more air and exchange more with each inhalation and exhalation, and their red blood cells carry more oxygen. They reduce the number of breaths they take during these sleeping/rest periods.

Also, they have a higher tolerance for carbon dioxide (CO2), and so their brains do not trigger a breathing response until their CO2 levels are much higher than what humans could tolerate. All of these mechanisms are adaptations to living in a marine environment.

Harbour porpoise, common dolphin, bottlenose dolphin, minke whale, humpback whale and fin whales are some of the most common species reported to our sighting scheme.

There have been 8 species of dolphin found in Irish waters.

For reasons not fully understood, bottlenose dolphins such as Fungi are sometimes encountered living on their own and are termed ‘social-solitary dolphins’. Cases of social solitary dolphins have been reported from all over the world and span several decades. The vast majority are bottlenose dolphins, but many other species have been reported. There are other solitary bottlenose dolphins in Ireland including Dusty in Clare and the Aran Islands and Nimmo in Galway city. More information on social solitary dolphins can be found here

In the wild, dolphins can be very long lived, and their lifespan varies between species. Orcas are on average believed to live for up to 50-80 years old. The oldest documented living orca was J2 aka ‘Granny’, a 103 year old female of the Southern Resident pod.

The largest species of dolphin is the orca/killer whale. Despite their common name of ‘killer whale’, they are in fact members of the dolphin family.

They don’t need to drink the way we do as their main prey (fish) has a high water content, so they gain water from their food.

A calf will nurse for up to two years after birth and may stay with its mother anywhere from three to four years after that.

Cetaceans evolved from land mammals, and many features characteristic of mammals (such as the presence of hair) were lost in the evolutionary process. All modern cetaceans now lack hair on their body overall however, some species retain a few hairs on their face and in other species hairs are found on neonates.

Yes, they have acute eyesight both in and out of the water and their eyes are capable of functioning independently. In situations where vision is not sufficient i.e. at great depths of distance, they can use echolocation to sense their environment.