Rarest of the rare

The Wildlife Conservation Society has released it's 2010-2011 edition of State of the Wild - A Global Portrait. It contains their listing of the Rarest of the Rare List, a group of animals considered to be among those most in danger of extinction. It's a slightly biased list - not an invertebrate to be seen - but it still brings some attention to some species in trouble. The list includes a single amphibian (an immediate indication of incompleteness), two reptiles, one bird, and six mammals.

Among those staring the grim reaper in the eye (with links to the IUCN Red List profile)...

The green-eyed frog, Lithobates vibicarius, a small ranid frog with a few hundred individuals surviving in Costa Rica and Panama. This little guy seems to be falling victim to the the fungal disease chytridiomycosis.

The Cuban crocodile, Crocodylus rhombifer, is a moderately-sized crocodile with a population of perhaps 4,000 individuals. The primary threats are loss of habitat, illegal poaching for meat, and hybridization with the more common American crocodile.

The ploughshare tortoise, Astrochelys yniphora, a native of Madagascar which may number fewer than 200 individuals in the wild. You may recall that we discussed the ploughshare's congener, A. irradiata, just last week. The ploughshare is falling victim to habitat destruction and the illegal pet trade.

The Grenada dove, Leptotila wellsi, a native of the island in the Lesser Antilles. Leptotila has a very small local population tha thas been hammered by habitat loss and hurricanes. As few as 30 reproductive pairs remain.

The Florida bonneted bat, Eumops floridanus, was believed extinct for several years, but there have been scattered sightings in south Florida and a small colony apparently persists in Fakahatchee Strand. The bats are sensitive to habitat loss, particularly the removal of cavity trees. Pesticide spraying for mosquitoes may be responsible for their decline over much of south Florida.

Hunter's hartebeest, Beatragus hunteri, is one of Africa's most threatened antelopes. The numbers remaining in their original range are uncertain, probably less than 1,000. A translocated population in Tsavo National Park numbers some 100 individuals. Also known as hirola, they have suffered due to hunting, habitat loss, and competition with livestock.

The island gray fox, Urocyon littoralis, is found on six of California's Channel Islands. It's the U.S.'s smallest fox. A major impact has been predation by golden eagles, although diseases like canine distemper may have also played a role in their decline. Population estimates the put the surviving numbers at perhaps 500 animals.

No list of the critically endangered would be complete without a primate - this one has two. First is the Sumatran orangutan, Pongo abelii. Around 7,000 of these apes survive on the northern part of the island of Sumatra. The primary threat is habitat destruction through logging, both legal and illegal, as much of the region's forests are converted to agricultural land and palm plantations. Animals are also captured and killed, but this appears to result primarily as the result of habitat conversion as the poor orangutans just can't understand that it's not their jungle any longer.

One of the lesser-known animals on the WCS list is the vaquita, Phocoena sinus, a small oceanic porpose native to the northern parts of the Gulf of California. They probably number less than 1,000, the result largely of drowings resulting from entanglement in gill nets.

Our second primate is the white-headed langur, Trachypithecus poliocephalus. Hunting and habitat loss have left a population of some 60 monkeys on a small island off the coast of Vietnam. Why hunt them? Well, your quant little Chinese apothecary needs it's supply of monkey balm.

Thrown in with the bad news - a little good. State of the Wild includes an account of two species that seem to have turned the corner toward recovery. The lucky ones? Przewalski's horse (Equus ferus) and Rober's tree frog (Liuixalus romeri).