Wolf Depredation 2. Perspective On Losses Do Wolves Inevitably Kill Livestock? It is widely believed that wolves only kill the easiest animals to catch. Why chase swift quick-witted and potentially dangerous deer armed with flailing hooves and stabbing horns when slow-moving defenceless sheep are all around? Of course wolves kill livestock animals. But do wolves inevitably kill them all the time? Wolves On The Range There are wolf packs in North America surrounded by farmland but, interestingly, they normally do not molest or kill the livestock around them. Wolves have lived on the Agassiz National Wildlife Refuge in north-west Minnesota since the 1980's, for example, and are entirely surrounding by farmland. The perceived threat of these wolves to the livestock prompted research on their habits in the late 1990's. Seventeen wolves were caught, radio collared and studied for 17 months around the clock (Gese 2003). The finding were that the wolves were active mainly at night and made forays from the reserve throughout the year into the farm land. The wolves on their treks frequently passed several groups of livestock without molesting them. Instead they fed on wild prey, mainly moose, white-tailed deer and muskrats. Wolves in the area did occasionally kill livestock, but on average only once a year. So it turns out that the risk to livestock from wolves in Agassiz is minimal. Ironically, before the study, people thought it best to destroy these wolves to avoid wolf-livestock friction. Livestock Toleration The same wolf toleration for livestock is noted elsewhere in the US and western Canada (eg Fritts et al 1992; Mech 1995; Bangs et al 2001). Therefore wolves co-existing amicably with livestock might be common and widespread. Of course, just because some wolves are livestock-friendly it does not mean that livestock toleration is necessarily inevitable by wolves in all situations. There may be many regions where circumstances are such that wolves do not co-exist amicably most of the time with livestock. Nevertheless, the findings show that wolves do not necessarily kill livestock all the time. This stands to reason, because if wolves always took the easiest prey, then they would always live entirely on livestock where wolf and livestock range overlap, which is not found to be the case. But this raises a major question. Why do wolves not kill more livestock than they do? This is tackled on the next page: 3 - Livestock Toleration. How Much Livestock Do Wolves Kill? Full and reliable statistics about wolf depredation in past times are rare. Records were simply not kept or, if they were, are meagre and incomplete. However, statistics of wolf depredation were started recently in North America and they are the most reliable records of wolf depredation.

Home - Wolf Trust Home - Thinking Wolves Wolf Depredation 1 Introduction 2 Perspective On Losses 3 Livestock Toleration 4 Verifying Wolf Kills 5 Economic Impact 6 Wolf-Killed Dogs 7 Surplus Killing 8 Conclusions 9 References

Wolves were widespread in the US but in the lower 48 presently live in only eight states: Arizona, Idaho, Michigan, Minnesota, Montana, New Mexico, Wisconsin and Wyoming. About 17 percent of cattle and 30 percent of sheep in the US live in these states (Meier 2001). (Wolves live in Alaska but depredation there is not an issue because there is no large scale livestock ranching.) Table 1 shows the total number of livestock the wolves living in these eight states are verified to have depredated over a number of years for which there are data. (Verified means an animal was objectively investigated to have been taken by a wolf, see 4 - Verifying Wolf Kills). Take Minnesota for example, where there are more wolves than all the other states combined. Since 1979, when there were a few hundred wolves, their number has grown to 2,500. During these 22 years the wolves have killed 1,200 cattle and fewer than 900 sheep. That is less than one livestock animal per wolf per year. Thus the number of livestock animals wolves kill in the US is very low. It is so low that even if you assume the number of depredated livestock is several times larger because of counting error, it would still be very low.

Table 1. Verified Wolf Depredation in the USA State Years Wolves per state Cattle killed Sheep killed Dogs killed Fowl killed Arizona - New Mexico 1998 22 0 0 1 0 Idaho 1995-2001 261 56 170 10 0 Michigan 1991-1998 245 4 0 1 0 Minnesota 1979-2001 2500 1200 879 173 1251 Montana 1987-2001 84 91 68 10 0 Wisconsin 1976-1998 250 45 11 27 142 Wyoming 1995-2001 218 41 256 23 0 See notes on right. Depredation In Canada Much the same story of wolf depredation can be said for at least parts of Canada where statistics are known. For example, over 4,000 wolves live in Alberta. Around 1,500 of them are found where they may cause problems with livestock. But although 235,000 to 300,000 cattle lived in wolf range from 1974 to 1990 only an annual average of 235 cattle was lost to wolves.

Table 1 An additional 24 animals - goats, pigs horses, donkeys and llamas - were also killed but are not entered in the table. All but a few of the fowl are turkeys. Wolf populations are constantly growing, so wolf numbers are based on 1998 figures for Arizona, New Mexico and Minnesota, 1999-2000 for Michigan and Wisconsin, and 2001 for wolves in Idaho, Montana and Yellowstone. Wyoming includes Yellowstone National Park. Data for from Arizona/New Mexico & Michigan are from USFWS 2000; for Idaho, Montana & Wyoming from USFWS 2001; for Minnesota from Wildlife Services 2002; and for Wisconsin from Willging et al 1999.

Lies, Damn Lies & Depredation We must always see statistics in perspective against their broader background to evaluate them properly. Therefore we must know how many cattle and sheep die from all causes in order to gauge how serious a problem wolf depredation is in the US. Table 2 shows the number of cattle and sheep dying from all causes of mortality and dying from depredation by all predators in the same eight states listed in Table 1. Minnesota is included in the eight states and again shown separately because it is the only state with a substantial wolf population and therefore deserving separate attention. Table 2. Numbers of cattle & sheep dying from all causes & from predation   Number Cattle % Number Sheep % Minnesota: All causes 172,900   30,000     Predation 2,100 1.2 3,200 10.7 8 States: All causes 841,000   430,000     Predation 16,600 2.0 193,300 45.0 See notes on right. You can see from Table 2 that the number of cattle dying from depredation from all species of predator is just a tiny fraction of deaths from all causes of mortality. The proportion of sheep killed by predators is much higher than the proportion of cattle killed by predators. This is due in part to the large number of sheep taken by coyotes (Canis latrans) and dogs. Coyotes account for 70 percent of the sheep killed in all the states combined. Coyotes and dogs account for 82 percent of the sheep killed in Minnesota. What are the chief livestock killers? The three main causes of death for the livestock in Table 2 are disease - particularly digestive, respiratory and birth problems - severe weather, and depredation of sheep by coyotes (NASS 1995; APHIS 1997). Conclusion Wolf depredation is obviously inconsequential to the livestock industry of all the states in the US with wolves. In Canada it is inconsequential to the livestock industry at least in Alberta. When wolf depredation is seen in perspective against cattle and sheep losses from all causes it is just a speck of overall livestock deaths. This is not to say that wolf depredation is unimportant to individual farmers, and this is discussed under: 6 - Economic Impact. © Wolf Trust 2004. All rights reserved.

Table 2 Predators are bears, wolves, coyotes, dogs, cougars, bobcats, foxes and eagles. The figures are for representative years for which statistics are available. Adult cattle and calves are for 1995 and are from APHIS 1997. Adult sheep and lambs are for 1994 and are from NASS 1995.