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People for the Ethical Treatment of Animals (PETA) is the largest animal rights organization in the world, with more than 3 million members and supporters.

PETA focuses its attention on the four areas in which the largest numbers of animals suffer the most intensely for the longest periods of time: on factory farms, in the clothing trade, in laboratories, and in the entertainment industry.

In addition, PETA works actively on many other issues, including the cruel killing of beavers, birds, and other "pests" as well as cruelty to the domesticated animals.

 
Category: Currents | Views: 741 | Added by: nickyurchenko | Date: 2012-07-12


In 1997, Ivlev has published the results of his laboratory feeding experiments with several tens of common carp, Cyprinus carpio, divided into four training groups. In training Group 1, fish were fed only chironomidae larvae (bloodworms), in Group 2  sideswimmers, in Group 3  water louses, and in Group 4  freshwater molluscs, respectively.

After 10 days of training, fish of each group were moved on mixed, four-component diet contained the foregoing food items in equal parts. Interestingly, in this mixed diet fish selected predominantly familiar foods, remembered by them in the 10-day training period (see Table).

Table. Indexes of food electivity in common carp trained before to eat one species of food (Ivlev, 1977)

Food

Group 1
index of electivity

Group 2
index of electivity
Group 3
index of electivity
Group 4
index of electivity

Bloodworms,
Chironomus plumosus

+ 0.37
+ 0.19
+ 0.10
+ 0.12

Sideswimmers,
Corophium chelicorne

- 0.13
+ 0.28
- 0.19
- 0.21

Water louses,
Asellus aquaticus

- 0.15
- 0.17
+ 0.28
- 0.20

Freshwater molluscs,
Limnaea ovata

- 0.54
- 0.56
- 0.51
+ 0.20

In trophic ecology, this phenomenon is named an acquired food electivity (acquired feeding electivity).

Generally, an index of food electivity, denoted by letter E, can range from -1 (absolute rejection) to +1 (absolute preference). E=0 means that some food is not rejected and is not preferred (that is this food is indifferent on electivity for an eater).

In general and applied ethology, the same phenomenon is considered in the terms of search image. An acquired serch image forms in the long-term memory of an animal
during its learning (both in the nature or laboratory) and is used further as an etalon (template, specimen) to collate the receiving perceptual information. Without constant verification, an acquired serch image is forgotten within some time period.

In our context, search images can form in respect of food or live prey, their colors, odors and other stimuli.

In common carp (Ivlev, 1977), approximately 1.5 week of training is needed to form the relatively stable search images (with indexes of food electivity more than +0.20, see Table). Fish can switch from one search image to another, but after the corresponding training (learning). To form the more stable search images (with indexes of food electivity no less than +0.80), approximately 1 month of training is needed (Ivlev, 1977). ... Read more »
Category: Ethology | Views: 753 | Added by: nickyurchenko | Date: 2012-07-09

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