Giant owls vs solenodons

Here's something you don't see very often...


This illustration (by Peter Trusler) shows the large Pleistocene Cuban owl Ornimegalonyx oteroi battling with a solenodon. Ornimegalonyx has been mentioned here a few times before (use the search bar), but nothing substantive, sorry. Most sources mention O. oteroi as if it's the only named species of Ornimegalonyx. Actually, Arredondo (1982) named three additional ones: O. minor, O. gigas and O. acevedoi. And, by the way, the Ornimegalonyx owls weren't the only big owls on Pleistocene Cuba - there was also a particularly big eagle owl (Bubo osvaldoi Arredondo & Olson, 1994) and the two large barn owls Tyto noeli Arredondo, 1972 and T. riveroi Arredondo, 1972 (Arredondo & Olson 1994). There were a diversity of smaller owls too.

Typical factoids usually given about O. oteroi are that its remains were initially misidentified as those of a phorusrhacid (see Brodkorb (1961)), that it was over a metre tall, that it had notably robust hindlimbs, and that it was probably flightless and cursorial.


"Over a metre" might be too much, but might not: it comes from the 1.1 m height estimated by Arredondo (1976). The adjacent illustration, found online (sorry, I can't find the artist's name owl - but not human soldier - by Satoshi Kawasaki), shows how insanely big such an owl would really have been. What.. really? Wow. Like many people, my first encounter with this animal was actually with a very inaccurate and rather strange reconstruction published on a Cuban stamp in 1982 (see below). Anyway, the claim of flightlessness might not be correct: Mike Habib, some-time frequenter of Tet Zoo, has mentioned in-progress work on the flight abilities of this and other giant owls, and Storrs Olson - often quoted as saying that these owls had a reduced flight ability - is also on record as saying "I rather imagine that these birds could fly or glide to some extent" (Olson 1978, p. 106). Olson even noted the possibility that "it may have taken very little flying ability to capture juvenile ground sloths, which this great owl was fully large enough to do" (p. 106). The idea of giant, ground-hunting running owls is undeniably incredible and I wish there were substantive studies that backed it up (I don't think there are, alas).


I'm disappearing for a little while soon. Have inadvertently been the focus of all too much media attention over the last few days: somehow the news on the Ashdown maniraptoran seeped into the mainstream and everyone wanted a piece.

For previous articles on owls, please see...

Refs - -

Arredondo, O. (1976). The great predatory birds of the Pleistocene of Cuba Smithsonian Contributions to Paleobiology, 27, 169-187

- . 1982. Los Strigiformes fósiles del pleistoceno cubano. BoletÃn de la Sociedad Venezolana de Ciencias Naturales 140, 33-55.

- . & Olson, S. L. 1994. A new species of the genus Bubo from the Pleistocene of Cuba (Aves: Strigiformes). Proceedings of the Biological Society of Washington 107, 436-444.

Brodkorb, P. 1961. Recently described birds and mammals from Cuban caves. Journal of Paleontology 35, 633-635.

Olson, S. L. 1978. A paleontological perspective of West Indian birds and mammals. Academy of Natural Sciences of Philadelphia, Special Publication 13, 99-117.


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So it was basically an owl-secretary bird?

By gray Stanback (not verified) on 15 Jun 2011 #permalink

The Cuban Pleistocene avifauna never ceases to surprise me. It seemed to have been full of predators compared to the other Greater Antilles. Its probably a combination of Cuba's larger size combined with the efforts of local researchers, Arredondo in the past and now William Suarez. The other islands are probably quite rich as well, just that there are few (if any) people working in them. Even then the material found seems to be quite a lot, taking Puerto Rico as an example, Storrs Olson is still working on stuff he collected in the 1970's!

I recognise the artistic style of that reconstruction with the human silhouette; it's by Satoshi Kawasaki, who has a website on prehistoric life. It's all in Japanese though.

His entry on Ornimegalonyx is here.

And it seems like Satoshi's work inspired modifications, namely the addition of the silhouette of a soldier to indicate the size of these animals. You can see the new image here.

That reconstruction reminds me of the secretarybird. In fact, it could be a similar animal: Mostly terrestial, but with the ability of flying still there.

I wonder if it held a claw erect, to maintain the sharpness of an owl's killing talons (they're no phorusrhacids, with that beak) while running along the ground? Or perhaps that's an argument for flightedness.

Or maybe it adapted its toepads to improvise semi-'retractable' claws, so the tips didn't contain the ground as much during walking?

A regular "Flatwoods monster" right here...

By C. M. Kosemen (not verified) on 15 Jun 2011 #permalink

Figures of Ornimegalonyx unguals show them to be about similar in curvature and sharpness to those of other owls, but we don't know whether this was true of the keratin sheaths (data on burrowing owls would be interesting here). However, of possible interest is that owls often kill by constriction: their feet are extraordinarily powerful, and they crush and pierce the bodies of their prey. I suppose this makes it plausible that even a hypothetical blunt-clawed owl could still be an efficient predator of any prey small enough to be grabbed. I'll ask Denver Fowler to comment on this.

@7: Nah, the flatwoods monster was a Gray in an exoskeleton. The owl hoots were just to fool the humans. Really.

Semi-serious question: Is there enough of the O. oteroi's feet preserved to determine whether it used its talons as traditional owls do, or used them more like clubs, as secretary birds are purported to do?

By heteromeles (not verified) on 15 Jun 2011 #permalink

Congrats on the latest media attention. I love (sarcasm) the way the headlines call the Ashdown dinosaur the "world's smallest" above articles that quote Steve Sweetman saying it's Europe's smallest.

Thanks, Vasha - though I must say that I really didn't want the media attention (and my coauthor was on holiday). Couldn't afford the time (very busy with two big book chapters at the moment) and didn't want to see stories about a 7 mm single vertebra splashed all over the media!! Still, it was fun - those who follow me on facebook or twitter (@TetZoo) will have seen all the funny stuff about loaves of bread, vomiting with rage and getting beaten up by "roving gangs of palaeontologists".

PS - another story about a single theropod vertebra broke today.

The Ashdown maniraptoran is cool, but it's one vert...I don't understand the media sometimes.

This owl looks positively evil, and I'm reminded of the Great Owl in The Secret of Nihm. I'd never expected an owl to grow to such proportions, but then I never expected a family of geckos to turn into snake-mimics, so nature never ceases to surprise me.

Owls are awesome animals. Any ideas on this animals ecology. It could of made an efficient ground predator, or swooped down on unsuspecting prey from above.

My thanks to Darren for the plug; very timely in that I just recently brushed off that back-burner dataset and am again looking at the giant owls. My best data come from one of the giant barn owls (Tyto ostologa), and there is nothing to suggest flightlessness in them so far. Then again, they aren't as large as some of the other giant Caribbean owls. Storrs Olson made a great point about the giant owls to me while I was working in the collections, which is that owls typically have somewhat undersized sterna compared to other raptorial birds (note: raptorial, as in the ecotype, not "raptor" as in the clade), and this seems to have fueled some of the initial claims of flightlessness in the island owls. Apparently, some of the first workers to access the giant island owl material did not recognize this, and thought the giants had reduced sterna.

By Mike Habib (not verified) on 15 Jun 2011 #permalink

This is off topic, but what the hell.

Darren, I know you're interested in Dinosauroids, but did you know that Dougal Dixon once designed one?

You can see it starting at about the two-minute point in this video:
...a documentary about Dixon that can now only be found in Japanese.

It has more in common with Nemo Ramjet's than with Dale Russel's, and is pretty weird.

I recognise the artistic style of that reconstruction with the human silhouette; it's by Satoshi Kawasaki, who has a website on prehistoric life. It's all in Japanese though.

That site also has a section on creatures from the future. It's more silly than scientific, and every so often you'll see a silhouetted animal with a question mark on it. Click on it, and it will show a creature that has some sort of pop-culture reference or joke in its appearance. Well worth seeing, even if you can't read Japanese.

By gray Stanback (not verified) on 15 Jun 2011 #permalink

Owls are (relative) small-prey specialist constrictors. They have long claws (with low curvature), and short toes, on each digit (see Fowler et al for detailed discussion of functions). The pointedness of the claws enhances their hooking ability, but generally speaking, if the prey is suitably grasped in the "palm" of the foot, then blunt claws shouldn't affect the ability of the owl to constrict. IIRC there were some experiments (probably by Davide Csermely) where he blunted bird of prey claws to see if this affected prey dispatch ability. Piercing by claws is generally not a strategy used for prey dispatch.

Owls also tend to swallow their prey whole (which can constrain their prey size), although some owls will tear up prey before eating. Poor baby sloths...

Our article (lots of details about bird-of-prey killing strategies):
Fowler et al. (2009) Predatory functional morphology in raptors: Interdigital variation in talon size is related to prey restraint and immobilisation technique, PLoS One 4(11)

Cheers for the mention Darren!

PS. nearly finished post-review revisions on the nonavian theropod follow-up to this paper.

I wonder if this owl was really running. Is it possible to distinguish from bones if a bird was a good runner (like say a pheasant) or tends not to walk a lot (say modern owls and other pounce feeders).

Hm, this is one of those interesting studies where a relatively inconspicuous anatomical feature is actually highly functionally constrained in evolution and can tell a lot about the ecology of an organism- like the ocular ring bone Science paper of recent.

It'd be interesting to learn of what this might tell us about extinct giant avians like the phorusrhacids and teratorns- the latter of which especially since it's debated whether it's a scavenger or predator? Wikipedia is suggesting the secretary bird strategy of 'stamping out' small prey may be analogous to the phorusrhacids- but with their adze-like beaks I'd question that.

General question: are there any owl clades that do well colonizing islands (I'm thinking about the Pueo here)? Lots of big owls seems weird. Is it just that Cuba's so close to North America that it's a continental island, and the diversity of large-bodied owls is luck of the draw?

By heteromeles (not verified) on 17 Jun 2011 #permalink

There's so much we need to know about Cuban fauna, living and extinct. Adrian Tejedor recently rediscovered Natalus major in Cuba, which was previously known only grom fossils. Ross MacPhee unearthed a new species of Paralouatta from the Quaternary of Cuba, which could be a good dinner option for this giant Owl, if they weren't on a tree.

By Guilherme (not verified) on 18 Jun 2011 #permalink

I think I remember reading that *Ornimegalonyx* was phylogenetically closest to *Strix* owls, rather than to *Bubo* as one might expect. Is this correct?

Also, when talking about the avian predators of prehistoric Cuba one shouldn't forget the presence of the 'titan hawks',the condor *Gymnogyps varonai* and possibly a teratorn. This, along with flightless cranes, ground sloths, solenodons, nesophontids, monkeys and secondarily small(-ish) macaws makes for an extremely interesting and spectacular fauna.

Is it very likely that the other Greater Antilles had a comparable fauna, most of which simply hasn't been discovered yet? That being said, I know that ground sloths, monkeys and giant accipitrids are known from some of these islands.

"The idea of giant, ground-hunting running owls is undeniably incredible..."

How about some troodonts? My favorite trivia to drop on people is about how the ear canals of troodonts and owls have an unusual similarity, which might suggest a similarity in lifestyle. Maybe troodonts were primarily nocturnal mammal-hunters, and of course most of them couldn't fly, so there you go...


By CS Shelton (not verified) on 19 Jun 2011 #permalink


are there any owl clades that do well colonizing islands

In general, owls are not particularly good at trans-oceanic dispersal. But there are some notable exceptions, such as the rather hawk-like Ninox owls, which are widely distributed in the Australasian Region, including New Zealand and several smaller South Pacific islands.

Among individual species, the barn owl Tyto alba and the short-eared owl Asio flammeus, respectively, are remarkably good at colonising islands. Both are found in (for example) the Galapagos Islands, and the short-eared owl has even colonised Hawaii (where the barn owl also occurs nowadays, introduced by humans). Both of these species also occur in the West Indies but, of course, the Greater Antilles are continental rather than truly oceanic islands, and they are relatively close to the mainland.

Thanks Dartian.

By heteromeles (not verified) on 20 Jun 2011 #permalink

Interesting and amusing how the silhouetted human reference for the size of this extinct CUBAN owl is that of an AMERICAN Soldier with an M-16. Freudian slip or cynicism? By the way , this was meant as a light-hearted commentary.

By Eladio Fernandez (not verified) on 20 Jun 2011 #permalink

Regarding island-colonising by owls; I might add that the tiny scops-owls Otus (sensu stricto) have also been pretty good at it. They are found, for example, on most islands and islands groups in the western Indian Ocean, and molecular data suggest that scops-owls have colonised these islands on at least two separate occasions during the last circa 4 million years (Fuchs et al., 2008).

Various Otus species are also found on several SE Asian islands, but (surprisingly, given their dispersal capabilities) these owls seem never to have spread to Australia.


Fuchs, J., Pons, J.-M., Goodman, S.M., Bretagnolle, V., Melo, M., Bowie, R.C.K., Currie, D., Safford, R., Virani, M.Z., Thomsett, S., Hija, A., Cruaud, C. & Pasquet, E. 2008. Tracing the colonization history of the Indian Ocean scops-owls (Strigiformes: Otus) with further insight into the spatio-temporal origin of the Malagasy avifauna. BMC Evolutionary Biology 8:197, doi:10.1186/1471-2148-8-197

Cool illustrations. I drew it out from the papers full size, basing it on burrowing owl proportions (due to the terrestriality), and it came out at about 110cm tall. The sternum is pretty small, but I did not compare it to birds near the flighted/flightless line to see where it falls. I reconstructed it as a pouncer/ parachuter on my blog:…

Great article!