Common marmoset
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Common marmoset ( Callithrix jacchus ) |
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| ( Linnaeus , 1758) |
The common marmoset or -äffchen ( Callithrix jacchus ) is a primate of the family of marmosets (Callithrichidae).
features
Common marmosets reach a head body length of 18 to 25 centimeters, the tail is much longer with about 30 centimeters. Their weight is around 300 to 400 grams. Their fur is predominantly gray-brown in color, with a few light horizontal stripes running down the back. The tail is also striped. Their head is brownish, characteristic are the white, tuft-like hair that surrounds the ears. There is a white spot on the forehead, the face is hairless. The limbs are rather short, as in all marmosets there are claws instead of nails on the fingers and toes (with the exception of the big toe). Males and females look very similar and do not show sex dimorphism.
distribution and habitat
Common marmosets inhabit northeastern Brazil . Their original range reached from Maranhão or Piauí to the north bank of the Rio São Francisco . They are now also at home in other regions of Brazil, such as Bahia , Rio de Janeiro and Santa Catarina , but also in Buenos Aires . Their habitat are forests, although they can occur in different forest types. They can be found in the steppe-like caatinga as well as in the damp Atlantic coastal forests. They are adaptable and can also exist in plantations or parks.
Way of life
Common marmosets, like all marmosets, are diurnal. At night they sleep in tree hollows or in the lianas. In the trees they either walk on all fours or jump.
They live together in groups of two to 15 (average 9) animals. These groups are often organized around a fertile pair and also include other adults and young animals. The reproductive couple dominates the group, the ovulation of the subordinate females is suppressed, so that they are not able to reproduce. In this suppression, pheromones from the dominant animals could play a role. The territory of a group is very small and only covers around 0.7 to 6 hectares.
The group members communicate with each other through facial expressions, postures and chirping sounds. In an experiment, it was discovered that common marmosets exhibit altruistic tendencies. They gave conspecifics food without a reward or consideration - not even for reproductive purposes.
food
The diet of common marmosets consists mainly of tree sap and insects. Like all marmosets , thanks to their specialized teeth, they are able to gnaw holes in the tree bark in order to get to the tree sap. This specialized diet enables them to get by with small habitats and reduces food competition with larger, more fruit-dependent primate species. Hunting insects makes up around 24 to 30% of their time. To a lesser extent, they also consume fruits, seeds, flowers, mushrooms, snails, small vertebrates and eggs.
Reproduction
In captivity, common marmosets form almost exclusively monogamous pairs. In the wild, on the other hand, the mating behavior is likely to be more flexible; in addition to monogamous couples, there is also polyandry , i.e. a female - the dominant one - mates with several males.
The females are reproductive all year round and have a regular cycle averaging 28 days in length, similar to that of humans. However, there is no menstrual period or other external signs of the cycle.
After a gestation period of approx. 150 days, the female, as with all marmosets, usually gives birth to twins. Triplets are more common in captivity, and quadruplets very rarely. The young are very large - they reach around a quarter of the weight of the mother. Although the mother nurses her young, she can ovulate and be fertilized again within two weeks of birth, while in humans breastfeeding usually prevents further ovulation for several months. The fathers and also the other group members participate intensively in raising the young, they carry the young around and occupy themselves with them. After three months, they are largely weaned and sexual maturity occurs in the second year of life.
The life expectancy of common marmosets is around 12 years in the wild.
Common marmosets and humans
Common marmosets have been caught and used in animal experiments or made pets since the 1960s . As laboratory animals, they are still among the most frequently used primate species, but are bred for this purpose and no longer caught. The hunt for common marmosets for the purpose of keeping them as pets still occurs. Another threat is the destruction of their habitat, to which the animals are exposed in some places.
Due to their adaptability and their relative lack of demands on the habitat, the common marmoset monkeys are not endangered species, the IUCN lists them as not endangered ( least concern ). As mentioned above, they were also able to spread to regions that were not part of their original habitat.
Biologists and medical professionals use the common marmoset for research focusing on behavior, reproduction, neurology and toxicology.
In brain research in particular, common marmosets are used as model animals for research into human diseases, such as B. Parkinson's disease.
literature
- Thomas Geissmann : Comparative Primatology. Textbook, Springer, Berlin et al. 2003, ISBN 3-540-43645-6 .
- Ariane Thieß: Philosophy versus Emigration: Analyzes for Maximizing the Fitness of Adult Sons and Daughters of a Semi-Free Marmoset (Callithrix jacchus) Göttingen 2004, DNB 974500763 (Dissertation University of Göttingen 2004, 273 pages ( full text online free of charge PDF, 273 pages, 3.3 MB) ).
- Don E. Wilson, DeeAnn M. Reeder (Eds.): Mammal Species of the World. A taxonomic and geographic Reference. Johns Hopkins University Press, Baltimore MD 2005, ISBN 0-8018-8221-4 .
Individual evidence
- ↑ JM Burkart, E. Fehr, C. Efferson and CP van Schaik: Other-regarding preferences in a nonhuman primate: Common marmosets provision food altruistically. In: PNAS 104 (50), 2007, 19762-19766. online: ( [1] )
- ↑ ". The common marmoset (Callithrix jacchus) as a model in toxicology," toxicologic pathology ; 123-7 31 Suppl, 2003 Jan-Feb.
- ↑ http://www.dradio.de/dlf/sendung/forschak/973149/
- ↑ Markstahler, Uwe: Ocular dominance columns in the primary visual cortex (Area 17) of Callithrix jacchus (Primates, Ceboidea, Callithricidae) 86 p. 1998. Diss. University of Freiburg.
