Floatbag
| Floatbag | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Floating bag, drawing from Brehm's animal life |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name of the genus | ||||||||||||
| Chironectes | ||||||||||||
| Illiger , 1811 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Chironectes minimus | ||||||||||||
| ( Zimmermann , 1780) |
The water opossum or Yapok ( Chironectes minimus ) belongs to the family of possums . It is the marsupial best adapted to aquatic life .
distribution
The swimming buoy lives in rivers and lakes in southern North America , Central America and South America , from southern Mexico to northern Argentina .
description
_fur_skin.jpg)
The body of the buoy is streamlined and well adapted to aquatic life. His coat is water-repellent, on the hind legs he has, on the whole length of the toes webbed . The fur is silver-gray on the back with four wide black horizontal stripes, which are connected by a black line on the middle of the back. The two horizontal stripes over the front and rear legs extend to the legs. The head is predominantly black with a light bar above the eyes. The peritoneum is white. Only the front sixth of the tail is hairy, the rest is hairless and black, the tip is white. The paws are reddish brown or dark gray. The front paws are provided with fleshy tubercles that are sensitive to the touch. The body length of the floating baggers is around 25 to 40 centimeters, the bare, rat-like tail can be 27 to 43 centimeters long. The weight of the animals is between 510 and 790 g. The ears are round and hairless. The females' pouch is open to the rear, can be closed watertight and contains five teats. The males also have a pouch. However, this bag is only rudimentary and lies behind the scrotum . The cremaster muscle allows males to lift the scrotum so that it is protected by the walls of the bag while swimming, diving or walking around on land. As the only marsupials, swim bags have no cloaca but separate openings for the urogenital tract and intestines.
Habitat and way of life
Floating baggers live on slow and fast flowing rivers and lakes from sea level to altitudes of 1860 meters. Rivers with large amounts of sediment are avoided. In southeastern Brazil (subspecies Chironectes minimus paraguensis ) the animals occur exclusively in fast flowing waters, if possible with a stony ground and dense forest on the banks. In the Cerrado , the buoyant fish lives in gallery forests and on the banks of stagnant waters. Like most opossums, they are solitary and mostly nocturnal . You live in an underground structure , the entrance of which is just above the surface of the water. A ground nest made of grass and leaves serves as a resting place during the day. Floaters very rarely climb trees, but they are excellent swimmers and divers. Then they use the hind legs as paddles while trying to catch food with the front legs outstretched.
food
The diet of the floating baggers consists of crabs , mussels and fish. Slowly swimming fish such as cichlids or catfish that live near the bottom of the water are mostly captured. Occasionally they also eat crickets , aquatic plants and fruits. Floating baggers were also observed removing and eating bats of the species Spectacled Nose ( Carollia perspicillata ) and Yellow-shouldered Bat ( Sturnira nana ) from Japanese nets that were stretched over the water. Captive buoys ate dead mice, chicks, young rats, crabs, fish fillets, roe , cod liver oil and minced meat.
Reproduction
The most prominent feature of the floating baggers is the female's waterproof and airtight bag. Cubs can survive in low oxygen levels for several minutes during their mother's dives. The size of a litter is on average two to five young (maximum 4 in C. m. Paraguensis ). Swimming baggers are one of the fastest growing marsupials. Around 40 days after birth, the young animals no longer fit in the pouch, then their legs hang out while the head is still firmly attached to the teat . About a week later, they loosen up, but are still suckled and sometimes cling to the mother.
The life expectancy of the buoys is a maximum of three years.
Taxonomy and systematics
The first scientific description of the species comes from the German biologist Eberhard August Wilhelm von Zimmermann and was published in 1780. Zimmermann gave the species the name Lutra minimus , so assigned it to the otters . In 1811, the German zoologist Johann Karl Wilhelm Illiger introduced the genus Chironectes , which has remained monotypical to this day. The terra typica is Cayenne in French Guiana . In the family of the opossum rats (Didelphidae), the buoys belong to the subfamily Didelphinae and together with the opossums ( Didelphis ), the thick-tailed pouch rats ( Lutreolina ) and the four-eye pouch rats ( Philander ) form the Didelphini tribe .
Subspecies
According to the Handbook of the Mammals of the World , 4 subspecies of the buoyancy compensator are valid. These are:
- Chironectes minimus argyrodytes Dickey , 1928, south of Mexico ( Oaxaca and Tabasco ) and north of Central America
- Chironectes minimus minimus (Zimmermann, 1780), eastern and southeastern Colombia, Venezuela south of the Orinoco , Guyana to Maranhão , western Amazon basin
- Chironectes minimus panamensis Goldman , 1914, south from Nicaragua to Panama, north and west from Colombia, northern Venezuela, Trinidad , Ecuador and Peru
- Chironectes minimus paraguensis Kerr, 1792, southern and southeastern Brazil, eastern Paraguay, northern Uruguay ( Cerro Largo Department ), Misiones Province , Argentina
Future revisions of the genus using modern methods could change the status of the subspecies.
threat
Floatbaggers are rarely seen, but it's unclear how common or rare they actually are. Because they are nocturnal and inhabit inaccessible areas, they are difficult to observe. The IUCN classifies them as " not at risk ".
literature
- Ronald M. Nowak: Walker's Mammals of the World. Johns Hopkins University Press, Baltimore 1999, ISBN 0-8018-5789-9 .
supporting documents
- ↑ a b c d e f Diego Astúa: Family Didelphidae (Opossums). in Don E. Wilson , Russell A. Mittermeier : Handbook of the Mammals of the World - Volume 5. Monotremes and Marsupials. Lynx Editions, 2015, ISBN 978-84-96553-99-6 . Page 157 a. 158.
- ↑ Eberhard August Wilhelm von Zimmermann: Geographical history of humans and the four-footed animals. In addition to a zoological world chart belonging here. 3 volumes, Weygandsche Buchhandlung, Leipzig 1778–1783, OCLC 8766966
- ^ Johann Karl Wilhelm Illiger: Prodromus Systematis Mammalium et Avium. 1811.
- ↑ Lucila I. Amador, Norberto P. Giannini: Phylogeny and evolution of body mass in didelphid marsupials (Marsupialia: Didelphimorphia: Didelphidae) . In: Organisms Diversity & Evolution . tape 16 , no. 3 , January 11, 2016, ISSN 1618-1077 , p. 641-657 , doi : 10.1007 / s13127-015-0259-x ( researchgate.net ).
- ↑ Chironectes minimus in the endangered Red List species the IUCN 2008. Posted by: AD Cuarón, 2008. Accessed January 2 of 2009.
Web links
- Chironectes minimus (English)