Department of Physics, Chemistry and Biology (IFM)

   

Brief communication: Behavioural differences between red jungle fowl (Gallus gallus) and White Leghorn (Gallus gallus domesticus).

Captive environment may lead to unintentional changes in an animal’s genotype¹ that alter

thresholds for performing behaviours essential for survival in the wild². From an ex situ

breeding aspect, release animals should have a behavioural repertoire as close as possible to

that of their wild conspecifics. Therefore, it is of great importance that animals are as little

affected as possible by their captivity. However, it is not possible to completely avoid

changes, and according to Gilligan and Frankham³, wild animals are likely to adapt to captive

environment rapidly through unintentional natural selection.   From this aspect, I have

investigated the differences between two captive populations of red jungle fowl (Gallus gallus)

(RJF) and one of White Leghorn layers (Gallus gallus domesticus) (WL), focusing on social

behaviours. The red jungle fowl originated from two populations, one from Copenhagen zoo

(COP) and one from Götala research station (GOT). They have been in captivity for different

length of time and kept under different environmental conditions. The animals used in present

study were the second generation GOT and COP and the first generation WL hatched and

reared under identical conditions at Götala research station, in order to eliminate

environmental effects.

A group observation test focusing on social behaviours was carried out. Significant

differences were found in social distance between GOT and COP at the ages 14 weeks

(P=0.001), 18 weeks (P=0.000) and 22 weeks (P<0.001), but non between WL and any of the

others. The differences found were mainly due to different behaviours performed, such as

different foraging strategies, dust-bathing behaviours and other social interactions. This also

resulted in differences in position in the pen, with GOT spending more time on perches above

ground than COP and WL. A difference in foraging behaviours where COP had a more costly

foraging strategy than WL were seen but not documented. This is in agreement with previous

findings⁴ of wild-type fowl having a more costly foraging strategy than domestic fowl and

could explain the results in this study.

Even though no significant differences were found in any of the behaviours, there were some

indications of differences. According to Rushen⁵, chickens establish their dominance

formation during the age of 6 to 10 weeks. Since COP had a peak of aggressive behaviours

at 6 weeks old, but none of the others did, this may indicate a difference in dominance

formation between the populations, or a difference in aggressiveness in the populations. Such

differences may have effects on social structures of the animals. Modifications of social

structures may affect a species survival after being released. A difference in reaching sexual

maturation in females was also found, were the domesticated WL reached sexual maturation

at 16 weeks, followed by COP at 19 and GOT at 21 weeks. An earlier sexual maturation could

be an advantage in captivity, but it could also affect survivorship in the wild. In a number of

species, a reduced fitness has been found in captive animals that have been released back

into the wild ³.  

Since no significant differences in social behaviours were found between any of the

populations, a genetic difference cannot be confirmed. These findings are in agreement with

findings in the first generation of RJF⁶, but do not agree with findings in the original

populations at Copenhagen zoo and Götala research center ^6,7 . In the original populations,

there was a difference in social behaviours, which suggests that the environment affects the

performances of social behaviours. If this is the case, it stresses the importance of keeping

ex situ animals in an environment that as much as possible resemble the natural habitat of

the species in order to minimize unintentional changes affecting fitness in the animals.

Annika Håkanson

Master student at Linköping University,Sweden

References:

1. Price EO & King JA (1968) pp 34-45 in: Hafez ESE (eds) Adaptation of domestic animals. Lea and Febiger , Pennsylvania .

2. Kleiman DG (1989) BioScience 39, 152-161.

3. Gilligan DM, Frankham R (2003) Conservation Genetics 4, 189-197.

4. Schütz KE & Jensen P (2001) Ethology 107, 753-765.

5. Rushen J (1983) Applied Animal Behaviour 11, 55-66.

6. Håkansson J, Bratt C & Jensen P (2005) In press

7. Håkansson J & Jensen P (2005 Biological conservation 122, 431-439.