Late in his career, Philip Henry Gosse became convinced that ‘sea-serpents’ reported by proper English eyewitnesses were plesiosaurs. Gosse (1861) argued that a total lack of remains was not necessarily problematic since two cetaceans were also known only from sightings: ‘delphinus rhinoceros‘ and a ‘Delphinorhynchus‘ with “remarkable” white flippers which Gosse happened to observe. The later ‘sea-serpent’ researcher Bernard Heuvelmans (1968) picked up on Gosse’s account and interpreted it as an undescribed species of (probable) beaked whale, a notion which still shows up in cryptozoology books and websites. It’s a shame this purported ‘cryptid’ has never been critically assessed – so far as I can tell – since beaked whales have a long history of being difficult to detect. Gosse’s sighting, however, is also quite problematic and it can probably never be determined just what he saw. That won’t stop me from discussing it, of course.
Gosse (1851) observed that one of his mystery cetaceans had a head “exactly” like that of ‘Delphinorhynchus‘, with no furrow between the “forehead” and snout being visible. As for what ‘Delphinorhynchus‘ meant to Gosse, his account describes two species in the now-invalid genus: ‘D. micropterus‘ (“The Toothless Whale of Havre”) and ‘D. rostratus‘. The former is a synonym of the beaked whale Mesoplodon bidens whereas the latter appears to be Gosse’s unique name for the Rough-Toothed Dolphin, Steno bredanensis. These distantly related species have superficially similar heads due to a flat melon and medium-long beak, so Gosse’s cetacean probably had these traits as well. Gosse (1856) was familiar with other ziphiids (‘Hyperoodon bidentatus‘, ‘Diodon sowerbyi‘) but considered them distinct due to their battle teeth; curiously, the latter species is in fact another synonym for M. bidens. Gosse’s understanding of ziphiids was incredibly crude by modern standards, but the description of the head coupled with that of the body (elongated, small dorsal fin set far back) makes it seem likely his mystery cetaceans were beaked whales, and mesoplodonts at that.

‘Delphinorhynchus micropterus’ (top) and ‘Diodon sowerbyi’ from Gosse (1856). Is it me, or has the top one been _Steno_-ized?
Behaviorally, Gosse’s cetaceans could not have been less cryptic. They traveled in a “herd”, “trooping towards the ship” and then stayed with it for around 17 hours and 120 English miles (~190 km). Gosse (1851) made no mention of extended disappearances (due to diving) but did observe the cetaceans “romp and frolic, in the manner of Dolphins”, protrude their heads above the surface, swim on their backs and (as reported by an officer) even breach. The behavior Gosse observed was undoubtedly extreme, but has some precedence in ziphiids: Hyperoodon approaches boats more frequently than other ziphiids (enough so to result in heavy hunting) (Dalebout et al. 2006); large groups of Indopacetus have been noted to be very active at the surface and to approach ships (Anderson et al. 2006); encounter durations in one study of Hawaiian M. densirostris and Ziphius averaged 1.45 hours, with one lasting 8.3 h (McSweeney et al. 2007); another study of M. densirostris found a wide range of reactions to vessels (avoidance, keeping distance, approach) and while surface behavior was usually inconspicuous, tail-slaps, head-raises, porpoising, and even a breach were observed (Ritter and Brederlau 1999). I can’t find any observations of ziphiid diving behavior (apparently) being disrupted for so long, but still, stranger reactions to human presence has been observed – one group of Pseudorca reportedly following a ship from Brazil to the English Channel (Tomilin 1967), for instance.
Gosse’s sighting occurred at 19°1′ N., 45°42′ W. – the middle of the North Atlantic – which is within the ranges of Mesoplodon densirostris, M. europaeus and Ziphius; Hyperoodon ampullatus, M. bidens and M. mirus are other North Atlantic ziphiids which have been recorded within 10 degrees of latitude of the sighting (MacLeod et al. 2006). Before throwing around the label of ‘cryptid’, it’s critically important to at least review these species and how well they fit Gosse’s descriptions.
The ‘Delphinorhynchus‘ comparison strongly fits with M. bidens and M. europaeus, albeit only if Gosse overlooked the battle teeth in males or observed a group composed only of females and immature individuals. Female M. densirostris may fit, despite the arched jawline, but males are utterly unmistakable. M. mirus is iffy since for a mesoplodont it has a rounded melon and short beak. Ziphius, whose external appearance Gosse was probably unfamiliar with, has a very short beak and melon more pronounced than any mesoplodont, and is thus an unlikely candidate. Gosse (1856) demonstrated he was familiar with Hyperoodon.
Gosse estimated his cetaceans to be about 30 feet (~9.1 meters) in length (“or perhaps not quite so much”), a size only Berardius bairdii regularly exceeds (MacLeod 2005). H. ampullatus may reach 10 m, but is on average much smaller, with a median length of 6.4 m and modes of 6.1-6.2 and 6.4–6.5 m (MacLeod 2005); surprisingly, it really isn’t much longer than the mesoplodonts on average*. Cryptozoologists have a bad habit of interpreting size estimates literally, and considering that this took place at sea and Gosse had no prior experience with ziphiids, I see no reason to dismiss the candidates as a result of this size estimate.
* Ziphius: median 5.5 m, mode 5.4-5.5 m; M. mirus: median 4.76 m, mode 4.8-4.9 m; M. bidens: median 4.5 m, modes 4.5-4.6, 4.8-4.9 m; M. europaeus: median 4.23 m, mode 4.2-4.3 m; M. densirostris median 4.15 m, modes 3.9-4.0, 4.3-4.4 m (MacLeod 2005).
Gosse described his cetaceans as being black above and white beneath, which doesn’t quite fit any of the candidates. There does seem to be a tendency for at-sea observations to describe species with complex color patterns as “black” (the “Black Dolphin” Cephalorhynchus eutropia being a prominent example), so Gosse’s description isn’t particularly useful, aside from ruling out adult male Ziphius. Gosse also describe the “lips” and extremity of the beak as having a fleshy coloration, and it is worth noting that Ziphius sometimes has pinkish coloration on its head; I’m uncertain if the other species sometimes display this trait, which could be the result of thermoregulation. It is curious that Gosse made no mention of circular or linear scars, but his account implied he was never particularly close to the whales, so they may have been overlooked (along with the battle teeth?).
The trait Gosse felt was most significant were flippers that were white “even on their upper surface”, which contrasted strongly with the dark body. Some M. mirus appear to have partially light flippers, although the surrounding body isn’t exactly dark. I’m curious why Brett Jarrett illustrated some M. densirostris with striking white flippers, perhaps some individuals of that species have been documented with that trait in obscure publications. I’m not exactly convinced white flippers are a trait diagnostic of a new species and not outside the possibilities of individual or population variation. Ritter and Brederlau (1999) noted that some M. densirostris had “coloured” portions of the flippers and other body parts, apparently due to diatoms, so color variation is not necessarily even genetic.
All things considered, I would hesitantly suggest that Gosse observed a large group of Mesoplodon europaeus, possibly largely composed of females and juveniles. The species was discovered a few years before his sighting, but it wasn’t until after Gosse died that it was accepted as a valid species. In typical frustrating fashion, there’s really no way to be sure just what Gosse saw – however there’s also no reason to conclude it’s a new species. Even for beaked whales, a century and a half with no sightings or carcasses is really pushing it.
References:
Anderson, R., et al. (2006) Observations of Longman’s Beaked Whale (Indopacetus pacificus) in the Western Indian Ocean. Aquatic Mammals 32(2), 223-231. Available.
Dalebout, M. et al. (2006) Nuclear and mitochondrial markers reveal distinctiveness of a small population of bottlenose whales (Hyperoodon ampullatus) in the western North Atlantic. Molecular Ecology 15, 3115-3129. Available.
Gosse, P. (1861) The Romance of Natural History. Volume 1. Available.
Gosse, P. (1856) A Manuel of Marine Zoology for the British Isles. Available.
Gosse, P. (1851) A Naturalist’s Sojourn in Jamaica. Available.
Heuvelmans, B. (1968) In the Wake of the Sea-Serpents.
Jardine, W. (1837) The Natural History of the Ordinary Cetacea or Whales. Available.
MacLeod, C., et al. (2006) Known and inferred distributions of beaked whale species (Cetacea: Ziphiidae). Journal of Cetacean Research and Management 7(3), 271–286. Available.
MacLeod, C. (2005) Niche Partitioning, Distribution And Competition In North Atlantic Beaked Whales. Doctor of Philosophy thesis for the University of Aberdeen, Aberdeen, UK. Available.
McSweeney, D. et al. (2007) Site fidelity, associations, and movements of Cuvier’s (Ziphius cavirostris) and Blainville’s (Mesoplodon densirostris) Beaked Whales off the Island of Hawai’i. Marine Mammal Science 23(3), 666-687. Available.
Ritter, F. & Brederlau, B. (1999) Behavioural observations of dense beaked whales (Mesoplodon densirostris) off La Gomera, Canary Islands (1995–1997). Aquatic Mammals 25.2, 55-61. Available.
Tomilin, A. (1967) Cetacea. Mammals of the U.S.S.R. and adjacent countries. Volume 9.
…
Gosse (1851) p. 3-6:
An occurrence of much more zoological interest, however, the sight of a very rare, if not quite new, Cetacean, under circumstances peculiarly favourable to observation, demands a more protracted notice. Having been familiar with several species of Delphinidæ in former Atlantic voyages, I had taken for granted that I should meet with some in this; and wishing to settle the question whether any of the true Dolphins spout, I had studied the Order a little before sailing; and, in particular, had made careful sketches of the form of the head in all the genera, that I might not depend on that treacherous guide, memory.
November 22d. — Lat. at noon 19° 1′ N., long. 45° 42′ W.; the trade wind blowing a most exhilarating breeze, with fine weather. Between three and four o’clock p.m., a herd of large Cetaceans appeared astern, trooping towards the ship. They soon came up and began to play around us, continuing to romp and frolic, in the manner of Dolphins, all the evening; and even long after nightfall they were still in company, being plainly visible by the light of the moon. During this long time, I had many opportunities of observing them. They frequently protruded their heads from the surface; and then, presently, the huge round back, with a small dorsal far behind, was seen. In going along beside the ship, one would occasionally turn on its back, displaying the white belly, and in this position swim a short distance. The muzzle was lengthened into a snout, but, as well as I could judge from many exposures, it tapered gradually without a furrow, and resembled that of Delphinorhynchus. As nearly as I could estimate from a position aloft, by comparison with the ship, their length was about thirty feet, or perhaps not quite so much. The body was elongated, black above, white beneath; the swimming paws appeared white, even on their upper surface, but surrounded by dark colour on the body; —this is remarkable. The lips and extremity of the muzzle appeared, when projected from the water, of a flesh colour. They usually expired with a rushing sound, the instant the blow-hole was exposed, but did not, as far as I observed, spout. Once, however, I noticed a little cloud of steam sailing away on the wind, from the spot where one had just disappeared; it exactly resembled that appearance which succeeds the spouting of the common Rorqual (which I have seen many times), but as my eye did not catch the animal itself, I cannot positively say that such was its origin on this occasion. The evenings being cool and refreshing after the burning days, and being generally fair, and now lighted by the moon,
“—pura nocturno renidet Luna mari,—” *
we spend them on deck, as the pleasantest hours of the twenty-four. This evening, the wallowing and sporting of the Whales added a new interest; and at nearly eleven o’clock, we left them still in company.
November 23d.— On rising, we were surprised to find the Whales still attending us. I now had an opportunity of seeing the profile of one very distinctly, and of assuring myself that the form of the head was exactly that of the figured Delphinorhynchus, no furrow being visible between the forehead and the snout. One of the officers informed me that he had seen one of them breach, or leap clear out of the water. Soon after 8 a.m. they left us, having continued with us nearly seventeen hours, a period of extraordinary length, when we consider that the visits of frolicsome Cetacea to vessels rarely last more than half an hour or an hour. During the whole of this time, the ship had been running before a gallant breeze, and had proceeded nearly 120 English miles.
I have little doubt that the species was that very interesting and rare Cetacean known as the Toothless Whale of Havre, Delphinorhynchus micropterus. The small size of the dorsal, and its backward position, agreed well with the description of that species, and though these were nearly double the length of that celebrated specimen, this incongruity is of little moment, since that was evidently a young one. If this was, indeed, the Havre Whale, the occurrence in associated numbers of a species, hitherto known only by a solitary specimen, possesses an interest which will be readily appreciated by naturalists; if, on the other hand, it was distinct, it is, perhaps, still more interesting, as it proves the existence of a gregarious Cetacean of large size in the Atlantic, which has hitherto escaped the observation of zoologists. The white hue of the flippers, isolated amidst the dark colour of the upper body, would seem to favour the latter conclusion.I may add here that when we were off the west end of Porto Rico, I observed a shoal of Dolphins playing at a short distance; one of them in leaping fell in a perpendicular position, the tail downward, while the body was thrown into a double curve. I was thus enabled to see that the belly was of a bright rose-colour. Now this is the hue of the under parts of the other Delphinorhynchus (D. rostratus), which is about eight feet in length, and might well be mistaken, in the moment of leaping, for a true Delphinus. The coincidence is a curious one: especially as this species is nearly as rare as the former.