untitled

3 Carnivory. This is the classical concept of predation where the predator kills and

eats the animal prey.

4 Cannibalism. This is a special case of predation in which the predator and prey are

of the same species.

Table 10.1 compares caribou and reindeer populations in areas with different levels of

wolf predation (Seip 1991). Densities vary by two orders of magnitude, the highest

densities being in areas with few or no predators. The lowest caribou densities are

in areas subject to high and constant predation. Conversely, Fig. 10.1 shows, first,

that wolf densities are positively related to moose densities in Alaska and Yukon (i.e.

the highest wolf densities are in areas with the highest moose density). This suggests

that wolves are regulated by their food supply. Second, when wolves are removed

164 Chapter 10

Category Location Density/km^2

Major predators rare or absent Slate islands 4 – 8

Norway 3 – 4

Newfoundland (winter range) 8 –9

South Georgia 2.0

Migratory Arctic herds George River 1.1

Porcupine 0.6

Northwest Territories 0.6

Mountain-dwelling herds Finlayson 0.15

Little Rancheria 0.1

Central Alaska 0.2

Forest-dwelling herds Quesnel Lake 0.03

Ontario 0.03

Saskatchewan 0.03

After Seip (1991).

Table 10.1Density of
caribou and reindeer
populations in relation
to the level of predation.

25

20

15

10

5

0

0 200 400 600 800 1000 1200 1400

Moose / 1000 km^2

Wolves / 1000 km

2

Fig. 10.1Wolf density
is related to moose
density in Alaska and
Yukon. In areas where
wolves are culled (
)
moose can reach higher
densities than in areas
where there is little
culling of predators
(). (After Gasaway
et al. 1992.)

10.4 The effect of predators on prey density