Hispaniolan solenodon

Hispaniolan solenodon[1]
Hispaniolan solenodon
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Eulipotyphla
Family: Solenodontidae
Genus: Solenodon
Species: S. paradoxus
Binomial name
Solenodon paradoxus
Brandt, 1833
Hispaniolan solenodon range

The Hispaniolan solenodon (Solenodon paradoxus), also known as the Dominican solenodon, or agouta, is a solenodon found only on Hispaniola, the island shared by Haiti and the Dominican Republic. It was first described by Brandt in 1833. A similar but smaller species, Marcano's solenodon (S. marcanoi), once lived on the island, but became extinct after European colonization. All solenodon species belong to order Soricomorpha and family Solenodontidae.

Description and behaviour

Illustration

The Hispaniolan solenodon looks much like an oversized shrew. It weighs 0.6–1.0 kg (1.3–2.2 lb). Head-and-body length is 28–33 cm (11–13 in) and the tail is about 25 cm. It has brownish-red fur on most of its body, with a paler underside. The tail, legs, snout, and eartips are hairless. The forelegs are noticeably more developed than the hind legs, but all have strong claws useful for digging.

The head is very big in relation to its body, with a long rostrum and tiny eyes and ears partially hidden by the body fur. A unique feature is the os proboscis, a bone on the tip of the rostrum that supports the snout cartilage. The dental formula for the species is 3/3, 1/1, 3/3, 3/3 = 40. The second lower incisor has a narrow groove (Solenodon derives from the Greek for "grooved tooth"), through which flows a venomous saliva secreted by the submaxillary gland, making the solenodon one of only a handful of venomous mammals.

Both sexes are similar. Males have an unexposed penis and the testes are hidden deep within the abdominal cavity. Females have an irregular estrus, apparently unrelated to seasonal changes; they may have two litters of one to three young per year. Usually, only two of the offspring survive, because the female only has two teats, which are found near her buttocks. The young are weaned after 75 days, but may sometimes remain with the parents while subsequent litters are born and raised, so up to eight animals may share the same burrow. Solenodons may fight each other on first meeting, but eventually they establish a dominance relationship and live together in captivity in relative harmony.

A Hispaniolan solenodon has glands in the armpits and in the groin, which are said to give off a goat-like smell. It readily defends itself against one of its own kind and is apparently not immune to its own venom, since animals have been seen to die after fighting and sustaining minor wounds. It may also attack other animals savagely: a captive solenodon was reported to have attacked a young chicken and torn it to pieces with its strong claws before eating it. In moments of excitement, it may grunt like a pig or give bird-like cries, but when pursued, it stays motionless and hides its head, making it easy to capture.

The Hispaniolan solenodon was unknown to science for so long because it is nocturnal, a consequence of which is its highly developed senses of hearing, smell and touch. Also, they are not very numerous, so their influence in an ecosystem is practically nothing. During daylight hours, they stay in their burrows, trees, hollowed-out logs or caves, remaining hidden from view. When they do come out, they run on their toes with a stiff, ungainly waddle, following an erratic, almost zigzag course. The local people claim solenodons never run in a straight line. When a solenodon is alarmed and tries to move faster, it is very likely to trip.

Hispaniolan solenodons eat a wide variety of animals, including arthropods, worms, snails and small reptiles; they may also feed on roots, fruits and foliage, although one study found they refused all forms of vegetation. They probe the earth with their snouts and dig or rip open rotten logs with their claws. Solenodons in captivity have been seen to bathe often and to drink only when bathing.

Ecology

A specimen in the wild

Because of a lack of natural enemies, the Hispaniolan solenodon did not evolve defenses against predators, and it is a slow, clumsy runner. When feral dog and cat populations became established and small Asian mongooses (specifically Herpestes javanicus auropunctatus) were introduced to control rats in sugar cane fields, its future was jeopardized.

The Hispaniolan solenodon's habitat is usually wooded or brushy areas, frequently close to developed agricultural land, where they can dig their complex underground burrows. Habitat loss and predation by introduced species have contributed to making it an endangered species; its numbers have dropped dramatically during the last few decades. It was actually considered almost extinct until 1907, when it was found living in the interior of Hispaniola. It was not considered to be in immediate danger early in the 20th century. In 1966, it was found in several localities in the Dominican Republic. As of 1981, after extensive searching, the Hispaniolan solenodon was declared "functionally extinct" in Haiti, persisting only in the remote mountains of the south. In 1987, it was still found in both countries, but was thought to be particularly threatened in Haiti. As of 1996, it could still be found in both countries. Wildlife filmmaker Jürgen Hoppe has been able to film the Hispaniolan solenodon in various parts of the Dominican Republic during the last 18 years. The most recent sightings in the wild (with video evidence) were during the summer of 2008, when a team of researchers from the Durrell Wildlife Conservation Trust and the Ornithological Society of Hispaniola were able to trap an individual specimen. The researchers took physical measurements and DNA from it before releasing it back into the wild.[3]

The Hispaniolan solenodon appears to have a patchy distribution. Populations are found both within and outside protected areas such as the Jaragua, Del Este and Sierra de Baoruco National Parks. In Haiti, it is reported from La Visite National Park and the Duchity region of the Massif de la Hotte.[4] Its presence in Los Haitises National Park in the Dominican Republic is inferred, but unconfirmed.

Origins

In 2016, researchers at the University of Illinois and the University of Puerto Rico completely sequenced the mitochontrial genome for the Hispaniolan solenodon. The study confirmed that the Hispaniolan solenodon diverged from all other living mammals about 78 million years ago. The study also found that there was much greater genetic diversity among the northern population than the southern population. This timeline aligns well with a hypothesis on how the Hispaniolan solenodon came to inhabit the island of Hispaniola. Geologists speculate that the island was part of a volcanic arc that connected to Mexico around 75 million years ago. [5]

Conservation

The Hispaniolan solenodon was identified as one of the top ten "focal species" in 2007 by the EDGE Species project.[6] A collaborative conservation project funded by the Darwin Initiative (UK) was started in 2009 and is researching the species to conserve it.[7]

The species is fully protected by law. However, national parks in both Haiti and the Dominican Republic are threatened by deforestation and encroachment for farming and charcoal production. The US Agency for International Development and the Nature Conservancy are working with local nongovernmental organisations to improve protection and implement management plans for these parks (the "Parks in Peril" programme). A recovery plan for the isolated Haitian population, published in 1992, advocated comprehensive surveys, improved management of the Pic Macaya National Park, education campaigns, control of exotic mammals, and an ex situ breeding programme. These recommendations have not yet been implemented.

Two conservation research and education programmes funded by the Darwin Initiative have recently been established, focusing on solenodons in both countries: "Building evidence and capacity to conserve Hispaniola's endemic land mammals" (started 2009), and "Building a future for Haiti's unique vertebrates" (started 2010). These collaborative projects represent a partnership between the EDGE programme, the Durrell Wildlife Conservation Trust, BirdLife International, the Sociedad Ornitologica de la Hispaniola, the Dominican Republic National Zoo, Societe Audubon Haiti, and in-country project partners.

See also

References

  1. ↑ Hutterer, R. (2005). "Order Soricomorpha". In Wilson, D.E.; Reeder, D.M. Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 223. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ↑ Turvey, S. & Incháustegui, S. (2008). "Solenodon paradoxus". IUCN Red List of Threatened Species. Version 2011.1. International Union for Conservation of Nature. Retrieved 25 June 2011.
  3. ↑ "Venomous mammal caught on camera". BBC. 2009-01-09. Retrieved 2009-01-09.
  4. ↑ Samuel T. Turvey, Helen M.R. Meredith and R. Paul Scofield (2008). Continued survival of Hispaniolan solenodon Solenodon paradoxus in Haiti. Oryx, 42 , pp 611-614. doi:10.1017/S0030605308001324
  5. ↑ "Endangered venomous mammal predates dinosaurs’ extinction | Carl R. Woese Institute for Genomic Biology". www.igb.illinois.edu. Retrieved 2016-05-03.
  6. ↑ "Protection for 'weirdest' species". BBC. 2007-01-16. Retrieved 2007-05-22.
  7. ↑ "The Last Survivors project".

External links

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