The Guadalupe fur seal was feared extinct, gone the way of the dodo after being slaughtered by Russian and US hunters for their skins. None could be found at breeding grounds and as sightings elsewhere tailed off the species was consigned to history.
So why are there thousands of Guadalupe fur seals swimming off the coast of Mexico now? As naturalists gladly admit, reports of the species’ demise at the end of the 19th century were premature. Small numbers of the animals clung on in island caves and were rediscovered only decades later. The population is now thriving, with the latest estimate putting their number at 15,000 or more.
However, the case of the Guadalupe fur seal is far from unique — and more animals feared extinct could be waiting to be rediscovered. A survey of the world’s mammals published yesterday reveals that more than a third of species once feared extinct have since been spotted in the wild, in one case 180 years after the last confirmed sighting. Rare mammals that were considered dead, but later rediscovered were typically missing for 52 years.
The Guadalupe seal was hunted to apparent extinction by 1892, but a tiny colony was spotted on the island by two fishermen in 1926. After a failed attempt to sell two of the animals to San Diego zoo, one of the fishermen went back to slaughter the colony out of spite. He later turned up in Panama to sell the skins, but was killed in a bar brawl. The seals were only rediscovered and protected when a zoologist tracked down the second fisherman, who revealed their location on his deathbed in 1950.
One rodent, the Bahian tree rat, which lives in forests on the Brazilian coast, went missing in 1824. Despite efforts by conservationists, the animal was not rediscovered until 2004.
The bridled nailtail wallaby was once common in Australia, but seemed to die out in the 1930s. It was spotted in 1973 by a contractor who was preparing to clear an area of land. After he raised the alarm, the habitat was bought by the local parks service to save the animal.
Another creature, a small marsupial called Gilbert’s potoroo, was missing for 115 years before it was rediscovered in the south of Western Australia in 1994.
Diana Fisher, who led the survey at the University of Queensland, said the number of mammals going extinct was still accelerating despite large numbers of lost animals being found.
Conservation experts have already warned that the world is in the grip of the “sixth great extinction,” as imported species and diseases, hunting and the destruction of natural habitats deal a fatal blow to plants and animals.
Writing in the journal Proceedings of the Royal Society B, Fisher lists 180 mammals reported as extinct, feared extinct or missing since the year 1500. Of these, 67 were later found to be alive.
Animals that were picked off by new predators were rarely rediscovered, while those threatened by a loss of habitat or hunting by humans were more likely to be holding on in small colonies, she found.
The survey highlights the uncertainties in lists of extinct species, but Fisher said it should help conservationists target their searches for missing species by focusing on those most likely to be alive.