The Wonderful Features and Names of Some of Ireland's Toothed Whales
Over the last few months we have met some amazing members of the whale order, from the many surprising species of dolphin that inhabit Ireland's seas, to one of the greatest predators ever to hunt through Irish waters, the sperm whale. Although very varied in form, these whales all have something in common, which is that they belong to the same branch of the order Cetacea – the toothed whales. But they are far from the only toothed whales to live in or visit Ireland's vast territorial seas, and this month we will meet a fascinating collection of the other species that enrich Irish waters with their presence, and whose form and features have given rise to some very colourful names.
Since last month we met that gargantuan predator in Ireland's seas, the sperm whale (Physeter macrocephalus), it might make sense to begin this month's exploration of some of the other toothed whales with a relative of this marine leviathan, for it is not the only sperm whale in Irish waters. However, if we expected to meet yet another cetacean titan, we would be sorely disappointed. This is because the closest relative of the sperm whale found in Ireland’s seas is the pygmy sperm whale, or caisealóid beag in Irish (‘small sperm whale’), and it truly deserves those titles, being an absolute minnow compared to its colossal cousin.
While the sperm whale can weigh 63 tonnes, the pygmy sperm whale, at a weight of just 300–400 kilograms, can be up to 200 times lighter. Indeed, just how disparate their sizes are can be underlined by the fact that a large male sperm whale can guzzle about a tonne of food in a single day, two-and-a-half times the body weight of its diminutive relative. Also, at a length of only three to four metres, this pygmy does not even reach a quarter of the length of the largest, 19-metre-long sperm whales. The pygmy sperm whale does, though, share some features with its far larger relative, not least that waxy substance called spermaceti in the head, which it also uses to control its buoyancy in the water.
The pygmy sperm whale also has a similar barrel-shaped head to its monstrous relative, with a long, narrow lower jaw, although even then it cannot match it in proportion. While the sperm whale’s species name contains the element macrocephalus, meaning ‘big head’, the head accounting for up to a third of its body length, the second part of the species name of the pygmy sperm whale, Kogia breviceps, means ‘short-headed’, and it only accounts for around a fifth of the total body length. If less dramatic in size compared to the body, though, the head of the pygmy sperm whale is quite interesting in its own right, there being a curious crescent-shaped mark between the pale- or white-ringed eye and the flipper, known as the false gill.
It is unlikely, then, that any writer will be inspired by the dimensions of the pygmy sperm whale to pen a novel to match the drama and excitement of that about Moby Dick, the white whale. And the same can probably be said of a somewhat larger toothed whale in Irish waters that is also known as the white whale – the beluga.
Like the pygmy sperm whale, the beluga owes many of its names to an obvious aspect of its form – that ghostly white colour, as can be seen in the cover image above. The Irish name, míol mór bán, means the very same as the English name, ‘white whale’, while the common name ‘beluga’ itself simply comes from the Russian word for ‘white’. The second part of its species name, Delphinapterus leucas, is also a reference to its milky coloration, being derived from the Greek word leucos, meaning ‘white’. Interestingly though, this pale whale only attains its ivory skin at around the age of five or six years old, transitioning from the newborn purple brown to ever-paler shades of grey as it ages.
One of the most striking aspects of the beluga’s form is the dramatic melon on its forehead, which is composed of fat and oils, and it is the function of this feature from which one of the most interesting names for this toothed whale is derived. The melon appears to change in shape when a beluga emits a call, and this they do very often, the complexity of the sounds produced – including ‘moos’, ‘whistles’, ‘chirps’, and ‘clangs’ – leading some to bestow on them the title of ‘sea canaries’. As one expert has put it, ‘underwater, the din from a herd is reminiscent of a barnyard’.
Suitably, this white whale haunts the waters bordering white lands, its normal range confined to the sub-Arctic and Arctic regions. However, it does venture south on rare occasions, and it has been spotted in Irish waters a number of times over the last century, even as far south as Cork Harbour in 1988, while a recent three-year survey also recorded its presence in Irish seas. Sightings in general are rare, though, and this is partly due to a feature of its body from which its genus name is derived. Delphinapterus means ‘dolphin without a wing’, a reference to the fact that it has no dorsal fin – possibly an adaptation to resist heat loss in cold waters or prevent damage from sea ice – and the lack of this feature makes them that much harder to spot.
Despite its name as ‘dolphin without a wing’, though, the beluga is not a member of the dolphin family, Delphinidae, but a member of the toothed whale family Monodontidae, which has only one other living member, the narwhal, itself the holder of an extravagant moniker. The narwhal is known as the ‘unicorn of the sea’, as though it is similar to the beluga in general form, it also sports a fantastic, three-metre-long spiralled tusk, which is a dramatically elongated tooth. But though this truly-toothed whale has on very rare occasions been spotted in the waters around Britain, it has not so far been sighted in Irish seas.
There is one last thing we should say about the beluga before we leave it, which is that it should not be confused with the great white sturgeon that is also, confusingly, called the beluga. The great white sturgeon is a fish, and is probably best known for the eggs that are collected from it which are eaten as caviar. The beluga whale is, though, eaten itself, although not as some delicacy on the tables of the rich, but as a subsistence food of the Arctic Inuit.
However, beluga meat has probably rarely, if ever, passed the lips of an Irish person, given how infrequent are their visits to the island’s waters. Yet, there is a relative of theirs in Ireland’s seas which has likely ended up in the bellies of Irish people over countless generations – the common porpoise.
As its name suggests, the common porpoise is a very common species in the seas around Ireland – in fact, it is the most common of all cetaceans in Irish waters and is found all around the island’s coasts, often even in inshore waters which is why it is also called the harbour porpoise. It is also the smallest cetacean in Irish waters, weighing on average a paltry 45–65 kilograms, and measuring only between around 1.5 metres and 1.7 metres long, depending on the sex, females being slightly larger.
Being so common, it should be no surprise, then, that the common porpoise is the species which is most regularly stranded on Irish beaches, and this, allied with the fact that it is found in inshore waters, and in high numbers, means that it has been a part of the Irish diet for thousands of years. Whether acquired through strandings or from active hunting, common porpoise remains turn up in archaeological sites from widely different eras.
The earliest have been found in Rockmarshall, Co. Louth, as part of a kitchen midden – essentially a dump of domestic refuse including bones, shells, etc. – which dates to around 4000–3000 BC, the time when the first farmers arrived in Ireland. But remains have also been found in later sites, such as late Viking settlements dating to around 1000–1100 AD. Even as recently as the eighteenth century, meat from porpoises caught in Irish waters was being exported to England.
With its regular consumption by humans in the past, then, it seems only suitable that the name ‘porpoise’ relates to another mammal that has been eaten in great quantities by the Irish over the years – the pig. ‘Porpoise’ ultimately comes from two Latin words, porcus, meaning ‘pig’, and piscis, meaning ‘fish’, so ‘porpoise’ means ‘pig-fish’. Its Irish name, muc mhara, means much the same, translating as ‘pig of the sea’.
It has been suggested that the similarity noted between the porpoise and the pig is due to this cetacean having a great store of fat in the layer of blubber under its skin. However, it would also seem reasonable to expect that its equation with the pig by the ancients was at least partly down to just its form in general, possessing as it does a stout and portly body shape.
Overall the porpoise looks more or less like a small, chubby dolphin with a blunt snout, and it is, in fact, related to these more streamlined toothed whales. The scientific name of Ireland’s common porpoises is Phocoena phocoena, with phocoena simply being the Greek for ‘porpoise’, and from this name comes that of the porpoise family, Phocoenidae. The Phocoenidae, along with the dolphin family Delphinidae and the beluga’s family Monodontidae, comprise the superfamily Delphinoidea, which is the largest group within the toothed whales.
Our explorations this month, then, have given us a wider understanding of the toothed whales in Ireland's seas, introducing us to interesting members of the superfamily Delphinoidea which lie outside the dolphin family, while also making us starkly aware that not all sperm whales in the wide waters off Ireland's coasts are monsters of breath-taking dimension. And though toothed whales like the pygmy sperm whale and the beluga may belong to families which contain far more spectacular forms, hopefully this investigation of their features and names has shown that they are very interesting creatures in their own right, while our look at Ireland's porpoises has opened our eyes to something far from common, gifting us a rare glimpse into the lives and diets of the ancient Irish.