Hoffmann's two-toed sloth

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Hoffmann's two-toed sloth
Hoffmann's two-toed sloth ("Choloepus hoffmanni")

Hoffmann's two-toed sloth ("Choloepus hoffmanni")

Systematics
Order : Tooth arms (pilosa)
Subordination : Sloths (folivora)
Superfamily : Mylodontoidea
Family : Choloepodidae
Genre : Two-toed sloth ( Choloepus )
Type : Hoffmann's two-toed sloth
Scientific name
Choloepus hoffmanni
Peters , 1858

The Hoffmann two-toed sloth ( Choloepus hoffmanni ) is a species from the Megalonychidae family . It is distributed in central and parts of South America , but has a two-part distribution area. The habitat includes both tropical rainforests and partly deciduous forests in the lowlands and at higher altitudes. There the Hoffmann two-toed sloth lives solitary in the treetops and feeds largely on leaves and young twigs. The brownish fur and the lighter face as well as the hanging upside down in the branches are characteristic. Several subspecies are distinguished, the total population is not endangered. The Hoffmann two-toed sloth was first described scientifically in 1858. It is named after the German naturalist Karl Hoffmann .

description

Habitus

Hoffmann's two-toed sloth

The Hoffmann two-toed sloth reaches a total length of 57 and 71 cm, with females being on average slightly larger than males. The short and outwardly invisible tail, covered by fur, takes up 1.4 to 3 cm. The weight varies between 2.7 and 9 kg. It thus represents the smaller species of the two-toed sloth . In general, the head is small, but longer than that of the three-toed sloth . The ears have a round shape and are a maximum of 3.7 cm long, they are also hidden in the fur. The fur generally has a yellowish to lighter or darker brownish color. However, the face is usually tinted lighter, the muzzle region, on the other hand, remains hairless. Like the real two -toed sloth ( Choloepus didactylus ), the fur consists only of the top hair, an undercoat like that of the three-toed sloth does not exist. The longest hair, up to 17 cm, occurs in the shoulder area. Sometimes the fur shimmers green, depending on the incidence of light, which is due to a symbiosis with algae that live in the fur. This symbiosis probably serves the animal as camouflage from predators, the effect being strongest in the rainy season . The vertex of the fur does not lie on its back as in other mammals, but on the stomach so that the rainwater can drain off better. The long limbs are ideal for climbing and shackling in the trees. The front legs are slightly longer than the rear legs. The hands consist of two, the feet of three functional rays. These have long and curved claws that can be up to 6.5 cm long at the front and back. The rear foot length averages 13.2 cm.

Skull and dentition features

Skull of the Hoffmann two-toed sloth ( Museum Wiesbaden collection )

The skull is between 9.8 and 11.1 cm in length. The width of the cheekbones reaches an average of 6.3 to 6.7 cm, but behind the eyes it is around 3.5 cm. The not fully developed zygomatic arch is characteristic . However, at the front attachment it has an additional, downwardly directed bone process. As with all sloths, the dentition differs from that typical of higher mammals . There are five teeth per branch in the upper jaw and four teeth in the lower jaw, for a total of 18. The rear ones have a molar-like design, the foremost is conically pointed and thus resembles the canine tooth ; it is also separated from the rear teeth by a larger diastema . It also clearly protrudes over the back teeth and is sometimes visible from the outside when the mouth is closed. Incisors are not developed. The upper row of teeth reaches a length of 2.4 cm.

Sensory performances and vocalizations

In general, the Hoffmann two-toed sloth's sense of sight is poorly developed and only designed for short distances. Due to the strongly curved cornea of the lens of the eye , vision only reaches 3 to 4 diopters . The hearing largely covers a low-frequency range. The little-known vocalizations are also geared towards this. Young animals call their mother when they are separated from each other with whining or whining noises below 1.4 kHz, with the average length per call being 0.48s.

distribution and habitat

Distribution area of ​​the Hoffmann two-toed sloth

The Hoffmann two-toed sloth has a two-part distribution area: The northern populations inhabit central and the extreme northwest of South America from Honduras and Nicaragua to western Venezuela and west of the Andes along the Pacific coast to Ecuador . The distribution area of ​​the southern population is east of the Andes and extends from northern and central Peru over the extreme west of Brazil to central Bolivia . The sloth species occurs from sea level to higher mountain regions. In Costa Rica, for example, animals have been recorded up to heights of 3328 m, in Panama up to 1925 m and in Venezuela up to 1150 m. Especially in the populations in higher mountain areas, the fur is much more dense. The entire distribution area is given as around 1.6 million square kilometers. The majority of the distribution area of ​​the Hoffmann two -toed sloth overlaps with that of the brown-throated sloth ( Bradypus variegatus ), with that of its close relative, the actual two -toed sloth , there are only a few overlaps.

The Hoffmann two-toed sloth uses mountain and lowland forests as habitat, occurring in evergreen tropical rainforests as well as in partly deciduous forests and secondary forests. However, dry forests are largely avoided. However, animals have also been spotted in Costa Rica in cocoa plantations , where they sometimes cover longer distances to food crops. In Honduras, individuals could also be observed in open grasslands with dry vegetation and thorn bushes. The population density varies depending on the preferred habitat. On Barro Colorado Island in Panama it is 1.05 to 2.7 individuals per hectare, in the Andean region of Colombia 0.3 to 1.5 and in the lowlands of Colombia 0.2 to 0.8 individuals on a comparable area of ​​land .

Way of life

Territorial behavior

Hoffmann's two-toed sloth in the branches

The Hoffmann two-toed sloth is nocturnal and lives solitary, two or more individuals are rarely observed together. Most of the animals stay in the treetops of the trees, about 14 to 15 m above the ground. The sloth clings to the branches with its strongly curved claws and hangs upside down. In this way an animal moves over horizontal branches, the movements themselves being very slow and reaching a speed of around 500 m per hour (0.14 m per second). The daily distance covered is up to 300 m, which is significantly further than with the three-toed sloths . In the case of an animal on a cocoa plantation, it was possible to detect a nocturnal migration between two food trees by handing over a transport cable over a distance of 1500 m. The forest floor is only visited to get to another tree or to defecate , but the latter often takes place hanging in the branches. The species of sloth walks awkwardly on the ground; three feet usually touch the ground when walking. However, the Hoffmann two-toed sloth is a good swimmer. Like other sloths, it can sleep up to 20 hours a day in the wild, but this is rarely achieved; Here the rest time averages 13 hours, continuous activity times can be up to 7.6 hours. The Hoffmann two-toed sloth usually uses clusters of lianas to sleep . Individual animals have action spaces that vary in size depending on the type of landscape. On Barro Colorado Island in Panama, these vary from 0.4 to 3.9 hectares (an average of 2 hectares). In a cocoa plantation in Costa Rica, the average size of the action areas was 4.4 ha, whereas those of the males were significantly larger and reached up to 21 ha. As a rule, the action areas of the male animals border or overlap with those of the female, so that an average of 3.2 females occur in a male's territory. Only in their core areas do males show a certain territoriality.

food

The Hoffmann two-toed sloth has a purely vegetable diet. In addition to leaves and young shoots, it also eats fruits and flowers. Investigations in Costa Rica revealed 101 different tree species in which the sloth species stayed, about a third of which also served as a food resource. The preferred plants included ant trees , hammer bushes , cordias , figs as well as coral and cocoa trees . The latter two were most frequently visited, all the others rarely. In Colombia, Brownea is also a group of plants often used by the Hoffmann two-toed sloth. On average, an animal eats 350 g per day or 85 g per kilogram of body weight.

Reproduction

While the females become sexually mature at three to five years of age, the males may take a year longer. It is assumed that the mating season is all year round, but partly also depends on the seasons. The interval between two births is around 15 months. The mating takes up to two hours, with the individual acts of sexual intercourse During mostly just a minute interrupted by a twice as long break. After a gestation period of eleven to twelve months, sometimes only eight are given, the female gives birth to a young. The birth weight is 340 to 454 g, the length 22 cm. The newborn is fur-covered and has open eyes and fully developed and hardened claws. It climbs independently on its mother's stomach, where it spends the first months of life. The newborn begins to suckle milk for the first time within the first 24 hours, which then happens several times a day. A young animal drinks water for the first time after a week, and it consumes its first solid food after two to four weeks. In the same period of time it also begins to play or to shimmy around branches, while after at least seven weeks it goes on its own explorations. It is unclear when the weaning begins, but the young animal is independent of the mother at around six months at the earliest, but the process can take up to two years. Also after around six months, the mother animals no longer respond to the calls of the young animal. The life expectancy of the Hoffmann two-toed sloth in the wild is unknown; one animal lived to be 32 years old in human care.

Predators and enemy behavior

Among the most important predators include inter alia the Jaguar . Analyzes of excrement residues from Costa Rica revealed evidence of the Hoffmann two-toed sloth as prey in almost a quarter. In addition, the ocelot and the long-tailed cat also prey on the sloth, and rarely the coyote . Among the birds, the harpy is particularly noteworthy, with studies on Barro Colorado Island in Panama according to the Hoffmann two-toed sloth taking up to 56% of the total prey of the bird of prey. Furthermore, anacondas can be named as predators among the snakes. Animals in distress bare their teeth or strike with their sharp claws.

Parasites and commensals

Since the two-toed sloth has no undercoat, external parasites are not quite as common as the three-toed sloths. Typical ectoparasites of the Hoffmann two-toed sloth include ticks of the genus Amblyomma and mites such as Edentalges and Sarcoptes , as well as mosquitoes such as Aedes and Haemagogus as well as a wide variety of fly and butterfly species . Moths of the genus Cryptoses also live in the fur, but they are not parasites. The moths lay eggs in the dung of the Hoffmann two-toed sloth and release nitrogen compounds to the algae that live in the fur. By licking its fur, the sloth species ingests the algae and thus receives important supplements that are not provided by the rather low-energy leaf food.

Internal parasites are mainly tapeworms and coccidia . Protozoa such as Endotrypanum and Leishmania as well as the single cell Trypanosoma are also known. Above all, Leishmania is very often detected in the Hoffmann two-toed sloth, but it is largely immune to it, which suggests a long adaptation. However, in some regions the sloth species is considered a reservoir for these protozoa, which lead to leishmaniasis in humans . It is also known to carry the Oropouche virus , which is transmitted by mosquitoes such as " Culicoides " and which can cause Oropouche fever in humans .

Systematics

Internal systematics of recent sloths according to Delsuc et al. 2004
  Pilosa  

 Vermilingua (anteaters) 


  Folivora (sloths)  
  Choloepodidae  

 Choloepus (two-toed sloth)


  Bradypodidae  

 Bradypus (three-toed sloth)




Template: Klade / Maintenance / Style

The Hoffmann-two-toed sloth is adjacent to the authentics two-toed sloth ( Choloepus didactylus ) the second type from the type of the two-toed sloth ( Choloepus ). The position of the two-toed sloth within the subordination of the sloth (Folivora) is assessed differently. According to skeletal anatomical characteristics, most scientists favor an assignment to the Megalonychidae family . However, according to molecular genetic studies and protein analyzes from 2019, this is polyphyletic and includes both large ground sloths from South and North America and the forms of the West Indies . The individual groups are not closely related to one another. The investigations therefore advocate classifying the two-toed sloths in the monotypical family of the Choloepodidae , which in turn belongs to the superfamily of the Mylodontoidea . The three-toed sloths ( Bradypus ) are to be regarded as the next related group within the recent sloths, which represent their own, likewise monotypical family. The sloths, together with the anteaters (vermilingua), form the closer family group of the tooth arms (pilosa), an order within the secondary articulated animals (xenarthra). Molecular genetics studies have shown that sloths split off from their common lineage with anteaters in the late Paleocene around 58 million years ago. The two genera Bradypus and Choloepus , which are still alive today , separated from each other in the Oligocene around 29 million years ago. The lines of the two species of two-toed sloths formed in the Upper Miocene about 9 million years ago. Fossil finds of the Hoffmann two-toed sloth are unknown.

Today five subspecies are distinguished:

  • C. h. agustinus Allen , 1913; in the Andean valleys of Colombia , northwestern Venezuela, and northern Ecuador
  • C. h. capitalis Allen , 1913; on the Pacific coast west of the Andes from Colombia to Ecuador
  • C. h. Hoffmanni Peters , 1858; Central America and western and northwestern Colombia
  • C. h. juruanus Lönnberg , 1942; western Brazil , southeastern Peru , northern Bolivia
  • C. h. pallescens Lönnberg , 1928; Peru east of the Andes

Another subspecies, C. h. florenciae , established Ángel Cabrera in 1958, but today she is considered to be part of the two- toed sloth . In contrast, C. h. pallescens 1928 originally put by Einar Lönnberg as the real two-toed sloth.

The first description of Hoffmann-two-finger sloth was made in 1858 by Wilhelm Peters , who continued the type locality of Costa Rica stated. This was specified more precisely in 1980 by Ralph M. Wetzel with " Heredia , Volcán Barba". The species name honors the German naturalist Karl Hoffmann .

Danger

There are no known major threats to the Hoffmann two-toed sloth. However, some populations, especially in Colombia and Central America, are affected by the ongoing deforestation, which leads to the destruction or fragmentation of habitable habitats . In some regions of the range, the sloth species is hunted by indigenous groups. In Colombia in particular, individual animals, mainly young animals weighing less than 700 g, find their way onto the market and are also sold to tourists as souvenirs. Due to its large distribution area, the species is not threatened in terms of its population; the IUCN lists it as “not endangered” ( least concern ). The Hoffmann two-toed sloth is present in numerous protected areas.

literature

  • DP Gilmore, CP Da Costa, DPF Duarte: Sloth biology: an update on their physiological ecology, behavior and role as vectors of arthropods and arboviruses. In: Brazilian Journal of Medical and Biological Research. Volume 34, No. 1, 2001, pp. 9-25.
  • Virginia Hayssen: Choloepus hoffmanni (Pilosa: Megalonychidae). In: Mammalian Species. Volume 43, No. 1, 2011, pp. 37-55.
  • Nadia Moraes-Barros: Megalonychidae (Two-toed sloths). In: Don E. Wilson, Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, ISBN 978-84-16728-08-4 , pp. 104–117 (pp. 116–117).
  • Ronald Nowak: Walker's Mammals of the World. Johns Hopkins University Press, Baltimore 1999, ISBN 0-8018-5789-9 .

Individual evidence

  1. ↑ a b c d e f g h i j k l Virginia Hayssen: Choloepus hoffmanni (Pilosa: Megalonychidae). In: Mammalian Species. Volume 43, No. 1, 2011, pp. 37-55.
  2. ↑ a b c H. Hugh, Genoways, Robert M. Timm The Xenarthrans of Nicaragua. In: Mastozoologia Neotropical. Volume 10, No. 2, 2003, pp. 231-253.
  3. ↑ a b c d e f Nadia Moraes-Barros: Megalonychidae (Two-toed sloths). In: Don E. Wilson, Russell A. Mittermeier (eds.): Handbook of the Mammals of the World. Volume 8: Insectivores, Sloths and Colugos. Lynx Edicions, Barcelona 2018, ISBN 978-84-16728-08-4 , pp. 104-117 (p. 117).
  4. ^ GG Montgomery, ME Sunquist: Contact-Distress Calls of Young Sloths. In: Journal of Mammalogy. Vol. 55, No. 1, 1974, pp. 211-213.
  5. ↑ a b c D. P. Gilmore, CP Da Costa, DPF Duarte: Sloth biology: an update on their physiological ecology, behavior and role as vectors of arthropods and arboviruses. In: Brazilian Journal of Medical and Biological Research. Volume 34, No. 1, 2001, pp. 9-25 ( scielo.br )
  6. ↑ a b c Tinka Plese, Adriano G. Chiarello: Choloepus hoffmanni. In: Edentata. Volume 11, No. 2, 2010, pp. 129-130.
  7. ↑ a b c d Christopher Vaughan, Oscar Ramírez, Geovanny Herrera, Raymond Guries: Spatial ecology and conservation of two sloth species in a cacao landscape in limón, Costa Rica. In: Biodiversity and Conservation. Volume 16, 2007, pp. 2293-2310.
  8. ^ A b Adriano Garcia Chiarello: Sloth ecology. An overview of field studies. In: Sergio F. Vizcaíno, WJ Loughry (Ed.): The Biology of the Xenarthra. University Press of Florida, 2008, pp. 269-280.
  9. ↑ a b Juan Fernando Acevedo-Quintero, Diana Sánchez Granada, Tinka Plese: Abundancia y preferencia de hábitat de Bradypus variegatus y Choloepus hoffmanni durante la época seca en dos fragmentos de bosque seco en Arboletes, Antioquia, Colombia. In: Edentata. Volume 12, 2011, pp. 36-44.
  10. ^ M. Zachariah Peery, Jonathan N. Pauli: The mating system of a 'lazy' mammal, Hoffmann's two-toed sloth. In: Animal Behavior. Volume 84, 2012, pp. 555-562.
  11. ↑ Erica Taube, Joël Keravec, Jean-Christophe Vié, Jean-Marc Duplantier: Reproductive biology and postnatal development in sloths, Bradypus and Choloepus: review with original data from the field (French Guiana) and from captivity. In: Mammal Review. Volume 31, No. 3, 2001, pp. 173-188.
  12. ↑ Eduardo Carrillo, Todd K. Fuller, Joel C. Saentz: Jaguar (Panthera onca) hunting activity: effects of price distribution and availability. In: Journal of Tropical Ecology. Volume 25, 2009, pp. 563-567.
  13. ↑ Karen D. Sibaja-Morales, Melvin Cartín Núñez: Unusual predation of Hoffmann's two-toed sloth (Choloepus hoffmanni) by a coyote (Canis latrans) in Costa Rica. In: Edentata. Volume 18, 2017, pp. 88-91.
  14. ↑ Janeene M. Touchton, Yu-Cheng Hsu and Albert Palleroni: Foraging ecology of reintroduced captive-bred subadult harpy eagles (Harpia harpyja) on Barro Colorado Island, Panama. In: Ornithologica Neotropical. Volume 13, 2002, pp. 365-379.
  15. ↑ a b Karen D. Sibaja-Morales, Jaqueline B. de Oliveira, Ana E. Jiménez Rocha, Jorge Hernández Gamboa, Jorge Prendas Gamboa, Francisco Arroyo Murillo, Janet Sandí, Yessenia Nuñez, Mario Baldi: Gastrointestinal Parasites and Ectoparasites of Bradypus variegatus and Choloepus hoffmanni Sloths in Captivity from Costa Rica. In: Journal of Zoo and Wildlife Medicine. Volume 40, No. 1, 2009, pp. 86-90.
  16. ↑ Jonathan N. Pauli, Jorge E. Mendoza, Shawn A. Steffan, Cayelan C. Carey, Paul J. Weimer, M. Zachariah Peery: A syndrome of mutualism reinforces the lifestyle of a sloth. In: Proceedings of the Royal Society B. Volume 281, 2014, p. 20133006, doi: 10.1098 / rspb.2013.3006
  17. ↑ a b Frédéric Delsuc, Sergio F Vizcaíno, Emmanuel JP Douzery: Influence of Tertiary paleoenvironmental changes on the diversification of South American mammals: a relaxed molecular clock study within xenarthrans. In: BMC Evolutionary Biology. Volume 4, No. 11, 2004, pp. 1-13.
  18. ↑ Robert P. Anderson, Charles O. Handley, Jr: A new species of three-toed sloth (Mammalia: Xenarthra) from Panamá, with a review of the genus Bradypus. In: Proceedings of the Biological Society of Washington. Volume 114, 2001, pp. 1-33.
  19. ↑ Timothy J. Gaudin: Phylogenetic relationships among sloths (Mammalia, Xenarthra, Tardigrada): the craniodental evidence. In: Zoological Journal of the Linnean Society. Volume 140, 2004, pp. 255-305.
  20. ↑ Luciano Varela, P. Sebastián Tambusso, H. Gregory McDonald, Richard A. Fariña: Phylogeny, Macroevolutionary Trends and Historical Biogeography of Sloths: Insights From a Bayesian Morphological Clock Analysis. In: Systematic Biology. Volume 68, No. 2, 2019, pp. 204-218.
  21. ↑ Frédéric Delsuc, Melanie Kuch, Gillian C. Gibb, Emil Karpinski, Dirk Hackenberger, Paul Szpak, Jorge G. Martínez, Jim I. Mead, H. Gregory McDonald, Ross DE MacPhee, Guillaume Billet, Lionel Hautier, Hendrik N. Poinar : Ancient mitogenomes reveal the evolutionary history and biogeography of sloths. In: Current Biology. Volume 29, No. 12, 2019, pp. 2031-2042, doi: 10.1016 / j.cub.2019.05.043
  22. ↑ Samantha Presslee, Graham J. Slater, François Pujos, Analía M. Forasiepi, Roman Fischer, Kelly Molloy, Meaghan Mackie, Jesper V. Olsen, Alejandro Kramarz, Matías Taglioretti, Fernando Scaglia, Maximiliano Lezcano, José Luis Lanata, John Southon, Robert Feranec, Jonathan Bloch, Adam Hajduk, Fabiana M. Martin, Rodolfo Salas Gismondi, Marcelo Reguero, Christian de Muizon, Alex Greenwood, Brian T. Chait, Kirsty Penkman, Matthew Collins, Ross DE MacPhee: Palaeoproteomics resolves sloth relationships. In: Nature Ecology & Evolution. Volume 3, 2019, pp. 1121-1130, doi: 10.1038 / s41559-019-0909-z
  23. ↑ Gillian C. Gibb, Fabien L. Condamine, Melanie Kuch, Jacob Enk, Nadia Moraes-Barros, Mariella Superina, Hendrik N. Poinar, Frédéric Delsuc: Shotgun Mitogenomics Provides a Reference Phylogenetic Framework and Timescale for Living Xenarthrans. In: Molecular Biology and Evolution. Volume 33, No. 3, 2015, pp. 621-642.
  24. ↑ Manuel Ruiz-García, Diego Chacón, Tinka Plese, Ingrid Schuler, Joseph Mark Shostell: Mitogenomics phylogenetic relationships of the current sloth's genera and species (Bradypodidae and Megalonychidae). In: Mitochondrial DNA Part A. Volume 29, No. 2, 2018, pp. 281-299, doi: 10.1080 / 24701394.2016.1275602
  25. ^ A b c Alfred L. Gardner, Virginia L. Naples: Family Megalonychidae P. Gervais, 1855. In: Alfred L. Gardner (Ed.): Mammals of South America, Volume 1: Marsupials, Xenarthrans, Shrews, and Bats. University of Chicago Press, 2008, ISBN 978-0-226-28240-4 , pp. 165-168.
  26. ↑ Sergio Moreno, Tinka Plese: The Illegal Traffic in Sloths and Threats to Their Survival in Colombia. In: Edentata. Volume 7, 2006, pp. 10-18.
  27. ↑ Tinka Plese, Adriano G. Chiarello: Choloepus hoffmanni. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. ( [1] ); last accessed on April 26, 2014

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