Rabbit-like

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Rabbit-like
European hare (Lepus europaeus)

European hare ( Lepus europaeus )

Systematics
without rank: Synapsids (Synapsida)
Class : Mammals (mammalia)
Subclass : Higher mammals (Eutheria)
Superordinate : Euarchontoglires
without rank: Glires
Order : Rabbit-like
Scientific name
Lagomorpha
Brandt , 1855
Familys

The hare-like , lagomorpha or scientifically lagomorpha ( old Gr . Λᾰγῶς lagôs "hare" and μορφή morphḗ "form") are an order of the higher mammals counted to the superordinate order of the Euarchontoglires . The order consists of two families , the Pfeifhasen (Ochotonidae) and the hares (Leporidae) with a total of 70 to 80 species . The hare-like are mainly grouped together due to various features of the skull structure, the teeth and the structure of the hind legs and compared to the rodents (Rodentia).

External anatomy

Rabbits are small to medium-sized mammals, the length of which is 15 to 30 centimeters in most species, but some rabbits can reach up to 70 centimeters in length. The adult weight varies between 0.1 and 7 kilograms; for the extinct species Nuralagus rex a weight of up to 12 kilograms is assumed.

The tail of the hares is usually very short, but completely absent in the pigeon hares. The length of the conspicuous hind legs and ears is also variable; the latter are very long , especially in species from the desert regions, due to their use for thermoregulation . The coloration of the lagoon is mostly inconspicuous and, depending on the habitat, developed as a camouflage color. Whistling hares and hares of temperate climates also show a seasonal color change to improve camouflage . In many species of rabbit, certain areas of fur are more conspicuously colored and are used for communication - this mainly affects the tail (the "flower"), but also the ears (the "spoons") or areas of the flanks.

Alaska hare ( L. othus )

All lagoon animals have a dense coat, with hair types ranging from woolly to stiff and bristly awns . There are conspicuous sensory hairs on the face, known as the "hare's beard", which are distributed around the mouth area ( mystacial vibrations ) and over the eyes ( superciliar vibrations ). There are particularly rigid bristles on the soles of the feet, which here probably have the function of shock absorption. In return, the ball of the sole is usually missing and only the pika have ball of the toe and a ball of the wrist.

Between the nostrils and the mouth, a sensory pit runs through the upper lip, which gives the name of the "harelip" found in humans . The edges of the lip are turned inwards and form a hairy groove that is covered with glands and is known as the "cheek and cheek organ". The fur on the bridge of the nose is regularly pulled back during the “winking of the nose”, which is typical for rabbits.

The ears are particularly large with the rabbits. They are funnel-shaped and can be moved independently of each other for sound location. Pika have smaller and round auricles. They start wide on the head, have a noticeable flap of skin on the inner wall and are usually covered by long hair. The eyes are large and sit on the sides of the head, which enables an all-round view.

Internal anatomy

Skeletal structure

Mountain hare ( Lepus timidus ) in summer fur
Wild rabbit ( Oryctolagus cuniculus )

What is noticeable about the skeleton is the very lightly built skull, which is strongly perforated in the front part of the hares and is opened by a triangular skull window in the pigeon bunnies . The bone plates are very thin-walled. The nasal cavity is very large, as are the eye sockets. An important feature that distinguishes lagomorphs from other mammals is a circular hole inside the eye socket (fused foramina optica).

Rabbits have a total of 26 to 28 teeth. The teeth have superficial similarities to those of rodents , but the rabbit-like have a second pair of incisors , which is only developed like a pin and is hidden behind the larger pair ( duplicates ). The large incisors with enamel coated, rootless and grow throughout life. As with rodents, there is a gap ( diastema ) between the incisors and molars , the canines are missing. The premolar and molar teeth are broad and have deep transverse folds, open roots and also grow back lifelong.

The spine is very flexible and consists of 7 cervical , 19 to 22 thoracic and lumbar , 4 cross and 7 to 16 tail vertebrae . The latter are usually very small and form a correspondingly short tail. In the shoulder girdle can clavicles missing. Ten pairs of ribs are attached to the thoracic spine, the first eight of which are only connected by cartilage via the sternum and the last two. The pelvis is elongated and lies parallel to the sacral spine.

The front legs have five toes, of which the first, the thumb , is significantly shortened. Unlike most rodents, they cannot be used for grasping. The hind legs have four toes that are usually clearly extended. They are designed as ankle bones, the thighs are short and the lower leg bones ( fibula and shin bone ) are fused together to form a strong bone.

Organ systems

The internal structure of the lagoon corresponds essentially to that of the basic type of mammals. Special features are found primarily in the structure of the gastrointestinal tract and the genital organs .

The stomach is simply constructed as a glandular stomach , followed by the small intestine , as in all other mammals , which merges into the large intestine and at the same place into the very large appendix . This may take about ten times the stomach contents and is in the pikas only one and a half times as long as the animals themselves. The subsequent appendix contains a lot of lymphoid tissue and the pikas there are also several other, similarly constructed trailer.

Due to the very difficult to digest and cellulose-rich food, the stomach is incapable of effective digestion, which is why the appendix is ​​the main digestive area of ​​the rabbits ( cecotrophy ), in which the pulp is broken down with the help of an effective intestinal flora . The food digested in this way is passed on from the appendix to the large intestine. In order for the released nutrients to benefit the body, the animals have to ingest the pulp again. You excrete it as soft fecal pills ( caecotrophs ) and then swallow them again immediately, the nutrient absorption takes place during the next passage through the small intestine. The actual excrement , on the other hand, consists of hard excrement pills. This type of digestion is similar to that of ruminants , but in which the food is choked up, not ingested again.

The females have a double uterus ( uterus duplex ), the horns of which open separately into the vagina . In the case of the hares, the genital opening and the anus are separated by a dam (perineum), in the case of the whistle hares both lead instead into a flat joint outlet opening ( cloaca ). The penis of the male animals is drawn in at rest and laid back, the whistling hares, in contrast to the hares, have a penis bone . A 'real' scrotum is not formed because the corresponding skin modifications such as the tunica dartos are missing; one speaks therefore of scrotal pockets , in which the testicles lie under the skin. The scrotum lifter muscle ( Musculus cremaster ) forms a muscular covering around the testicle.

distribution

Rabbit-like are widespread almost worldwide. Originally they were only missing in southern South America , Madagascar , most of the Southeast Asian islands as well as Australia and the oceanic region.

Due to human influence, they are now spread around the world and are only absent in Antarctica . The worldwide distribution affects almost exclusively the European wild rabbit ( Oryctolagus cuniculus ), which as a meat supplier, domestic and hunting animal was settled wherever it could survive. Most species of the hare-like, on the other hand, are still restricted to more or less large areas of distribution.

Way of life

behavior

American pika ( Ochotona princeps )

Rabbits are usually ground-dwellers who inhabit a number of habitats - from deserts to tropical forests to arctic tundra. As a rule, they live in structures in the ground, especially the various rabbit species dig complex residential structures with individual underground chambers. In the wild rabbit, for example, there are short tubes that end in a padded nest. Other species such as the marsh rabbits and water rabbits build covered nests with side entrances. More complex residential buildings with several chambers, nesting areas, corridors and several exits, on the other hand, create a series of social rabbits and whistles. There are also pebbles and red rabbits that live on debris and use natural hollows and crevices. Most rabbits that live in more open landscapes use so-called sassen, depressions in the ground in which they set up their resting places.

The social structure of the rabbit-like species ranges from solitary species like most rabbits to social family groups, such as those found in some rabbits and piping hares. Pfeifhasen have a wide range of communication sounds, to which they owe their common German name. Some other social rabbits also have vocal sounds, but not with such a vocal range. In addition, the knocking with the hind legs is very pronounced, especially as a warning signal when there is potential danger. The posture and the presentation of color-conspicuous body parts as well as the use of fragrances also serve for communication.

As a rule, rabbits are not very defensive and are prey for a number of different predators . The most common protection strategy for them is to flee and avoid contact with the enemy. The animals are accordingly very vigilant and frightened and can only rarely be found at a greater distance from their burrows. Especially the hares that live in the open are also fast runners and can skilfully hit hooks to leave their pursuers behind.

nutrition

Hare-like are mainly herbivores that feed primarily on grasses and herbs, but also eat roots, twigs and bark. As shown in the section on anatomy, they are caecotrophic species. They excrete soft fecal pills and swallow them again immediately so that the nutrients released in the appendix during digestion can benefit the body.

Some species build supplies of hay and other plant parts in their burrows in order to bridge dry or cold seasons.

Reproduction and development

Many species are characterized by very high reproduction rates. However, the reproductive time of most lagomorphs is seasonally limited, with the photoperiod being an important factor for ovulation in females and also in spermatogenesis in males. Under permanent long-day conditions, they usually reproduce all year round . Tropical species, as well as species that have migrated from temperate climates to tropical regions, reproduce all year round. If the females do not mate during a fertile phase ( oestrus ), further ovulations follow one another at short intervals of 7 to 14 days. In addition, most species have a renewed oestrus, known as postpartum oestrus, only a few hours after the young are born. Ovulation itself is induced by copulation and occurs about 10 to 12 hours after this. The pairing itself only takes a few seconds, but takes place very often one after the other, whereby the partners can also change.

Depending on the species and climate, gestation lasts between 28 days for wild rabbits and more than 50 days for rabbit species that live in the polar regions. The young animals are used in all lagomorphs except the genuine rabbit (Lepidae) as Nesthocker (stock boy) on the world. They are mostly naked or only sparsely hairy and blind. The camp boys open their eyes after about 19 days and are usually independent after four weeks. The young rabbits, on the other hand, have fully developed eyes and hearing at birth and are already able to move. Accordingly, in contrast to the other rabbit-like species, the real rabbits do not build special nests for the young animals. For around two to four weeks, the young are suckled with a high-fat and protein-rich breast milk .

Skeleton of the fossil hare Palaeolagus haydeni from the Oligocene of North America

The reproduction rate of many rabbits is very high due to the short gestation and development period, early sexual maturity and the high number of litters with high litter numbers. Some whistle hares in the steppe areas can have up to five litters a year with 8 to 13 young animals each, while wild rabbits and some other species have five to seven litters with up to nine young animals each. Due to the high pressure of the enemy, the mortality rate among the animals is also very high.

Tribal history

The oldest fossils of rabbit-like animals date back to the Paleocene around 60 million years ago and were found in China. The representatives of this genus ( Mimotona ) share the characteristics of the rabbit-like. However, they have a number of other traits that identify them as an early side branch of the hare-like species, with a common ancestor. Fossils, which show a separation into the pika and hares, are about 30 million years old.

Systematics

 
 Glires 

Rodents (Rodentia)


 Hare-like (Lagomorpha) 

Pigeon hares (Ochotonidae)


   

Hares (Leporidae)




In contrast to earlier times, the rabbits are no longer placed in the order of rodents , although they form their tribal sister group. Because of the characteristics that can only be found in them, the monophyly of the rabbit-like is well founded. Their development history, which has been running separately for at least 60 million years, justifies the formation of a separate order. Rodents and rabbits can be traced back to a common parent species due to common characteristics such as the incisor teeth , which is why they are grouped together as a Taxon Glires .

The order is divided into two families: the worldwide spread hares (Leporidae) and the short-eared pikas (Ochotonidae) located on North America and northern Asia are limited. A third family, Prolagidae, was formed by the Sardinian pigeon hare ( Prolagus sardus ), which became extinct at the turn of the 19th century .

In the following systematics of the rabbit-like a classification is carried out down to the species level. The basis for this is the classification according to the classic system, with the Integrated Taxonomic Information System (ITIS) serving as the basis:

Classical systematics of the rabbit-like

Order hare-like (Lagomorpha)

Humans and rabbits

Easter bunny postcard (1907)

Almost all species of hare-like play a role in nutrition in the human cultures of their homeland. They are not infrequently important meat suppliers and have accordingly been hunted since the earliest times of human history. Many species, especially the various hares such as the brown hare or the mountain hare as well as the wild rabbit in Europe, also entered human cultural history due to this relationship and became part of human myths and stories. The most famous uses in the western cultural states include the Easter bunny and master lamp in fairy tales and fables such as the hare and the hedgehog .

Only a few species are suitable as pets, including above all the wild rabbit, which today is kept internationally as a domestic rabbit in hundreds of different breeds as a meat supplier and as a pet . Especially in Central Europe and North America, an own breeding culture has developed based on this, which is organized in rabbit breeding associations and regularly organizes breeding rabbit exhibitions. Most of the other rabbits and also the whistling hares, on the other hand, are difficult or impossible to keep due to their sometimes enormous space requirements.

Hunting and habitat destruction has resulted in a number of species becoming rare or threatened with extinction. The Bushman hare , the Sumatran rabbit and the pigeon hare species Ochotona argentata , all of which are listed as critically endangered by the IUCN, deserve special attention .

literature

  • Renate Angermann, Alfred Goldschmidt: Lagomorpha, game animals. In: Wilfried Westheide, Reinhard M. Rieger: Special Zoology . Part 2: vertebrates or skulls. Spectrum, Heidelberg 2004, ISBN 3-8274-0900-4 .
  • Jenny Bruce, Karen McGhee, Luba Vangelova, Richard Vogt, Jenni Bruce, Pavel Dvorský (illustrations): The Encyclopedia of Animals (Original title: The encyclopedia of animals. Translated by Christiane Gsänger). National Geographic, Hamburg 2007, ISBN 978-3-937606-95-8 , p. 18.
  • Ronald M. Nowak: Walker's Mammals of the World . 6th edition. Johns Hopkins University Press, Baltimore 1999, ISBN 0-8018-5789-9 (English).

Web links

Commons : Rabbit-like  - collection of images, videos, and audio files

Individual evidence

  1. ^ Anne Schulze: Anatomical peculiarities in rabbits (Oryctolagus cuniculus f. Domestica). In: Franz-Viktor Salomon et al. (Hrsg.): Anatomie für die Tiermedizin. 2., ext. Edition. Enke, Stuttgart 2008, ISBN 978-3-8304-1075-1 , p. 732.
  2. ↑ Don E. Wilson, DeeAnn M. Reeder (eds.): Prolagus . ( Memento of February 4, 2013 in the Internet Archive ) In: Mammal Species of the World. A Taxonomic and Geographic Reference. 3. Edition.
  3. ↑ Systematics of the Lagomorpha in the Integrated Taxonomic Information System (ITIS)
This version was added to the list of articles worth reading on July 2, 2006 .