useless natural history trivia IV
I hope y'all don't mind that most of this will be zoological or paleontological trivia, as those are the fields I know best.
1. There is a type of spider that feeds on human blood, but which never bites humans.
This is the vampire spider, Evarcha culicivora. It’s a kind of jumping spider found near Lake Victoria in Africa. It’s small – about half a centimeter long – and like other small jumping spiders, it actually can’t bite humans. Their chelicerae (fangs) can’t break our skin.
It feeds on blood by feeding on the mosquitoes that feed on humans and other animals.
2. Until humans first arrived in the West Indies, the land predators on many islands were giant flightless owls.
These actually arose at least twice independently from different flying owl ancestors. The form in Cuba, Ornimegalonyx oteroi, was a bit under 4 feet tall and was related to living barred and spotted owls (Strix). The one found in the Bahamas, Tyto pollens, is a giant barn owl. It was slightly smaller than Ornimegalonyx, but still taller than 3 feet.
Giant owls also appeared on other islands in the Hawaiian chain, Indian Ocean, and Mediterranean. The Hawaiian forms – so-called “stilt owls” – are thought to have been able to fly. Whether the other forms were flightless is unclear.
None of these was ever seen by a scientist, but the West Indian forms most likely survived until the earliest humans arrived, and may have even persisted until after European contact. The legend of the chickcharney – a three-foot-tall feathered,, mischievous, red-eyed, ghostlike creature in Bahamian folklore – is most likely a cultural “memory” of T. pollens. Neville Chamberlain was supposedly cursed by chickcharneys when he worked on a plantation in the Bahamas and scoffed at the legend.
(True story – a colleague of mine was excavating some subfossil deposits in the Bahamas many years ago, and he couldn’t get any of the locals to help him. They were afraid of the ghosts living in the caves. The ghosts they described would have looked and sounded a lot like a barn owl, though I don’t know if the word “chickcharney” was used.)
3. Animals on islands also become miniatures. This includes the miniature elephants that arose on many islands in the Mediterranean. These, too, arose independently from different large elephant ancestors. Those on Sicily, Malta, and the Aegean are related to Palaeoloxodon, an extinct elephant lineage related to African elephants. Those on Sardinia are miniature mammoths, and mammoths are more closely related to Asian elephants. Both types occurred on Crete.
The best-known form, Paleoloxodon falconeri from Sicily, stood about 3 to 3.5 feet tall. The dwarf mammoths were larger, but were still no taller than the average human.
Miniature mammoths also occurred on the Channel Islands off the coast of California. Other small elephants occurred in parts of modern-day Indonesia and the Phillippines, most of which are forms of Stegodon related to Asian elephants.
Whether modern humans saw any of these is unclear. One of them lived alongside the “hobbit,” Homo floresiensis, on Flores Island in Indonesia, but this one was probably extinct before modern H. sapiens arrived. But whether humans saw these elephants alive or not, discoveries of their skulls in the Mediterranean may have played a role in mythology. Someone who’d never seen an elephant, such as a seafarer from southern Europe during the Bronze Age, might have come across the skull of a miniature elephant. If you don’t know anything about elephants and see one of these skulls – especially if the tusks had fallen out, leaving two really big tooth sockets – it would be easy to confuse the large naris (nose hole) with an eye socket and the tooth sockets for nostrils.
The last surviving mammoths – those on Wrangell Island north of Siberia, which persisted until about 4000 years ago – were typically small, but they were at the low end of the size range for mainland mammoths.
For what it's worth - Island dwarfism and gigantism are well-known and widespread phenomena. There are/were giant tortoises on the Galápagos Islands and Seychelles, giant rabbits on Mallorca, and giant rodents pretty much everywhere. There were miniature crocodiles on Aldabra, New Caledonia, and Fiji. And the Flores Island "hobbit" (Homo floresiensis) is itself thought to be an example of island dwarfism.
4. Speaking of spiders - a giant fossil spider was featured in one of the "Walking With" series that featured CGI extinct animals in 2005. This was based on Megarachne, which was thought to be a nearly two-foot-long spider that lived about 300 million years ago. The problem? After the episode of Walking with Monsters featuring the beast started production, it was shown that Megarachne wasn't a spider at all - it belonged to a group called Eurypterida, which is only distantly related to spiders. (That said, some eurypterids were six or more feet long.). They couldn't retool the animation to show it as a eurypterid, so they just called it Mesothelae. Mesothelae is an assemblage of several types of primitive spider.
So far as I know, there have never been spiders anywhere near as large as Megarachne. That doesn't mean I'd want any of them on me.