Livestock guard dogs, traditionally used to protect farm animals from predators, are now being used to protect the predators themselves

传统上用于保护农场牲畜免遭掠食者侵害的牧羊犬，如今正被用来保护这些掠食者本身。

AFor thousands of years, livestock guard dogs worked alongside shepherds to protect their sheep, goats and cattle from predators such as wolves and bears. But in the 19th and 20th centuries, when such predators were largely exterminated, most guard dogs lost their jobs. In recent years, however, as increased efforts have been made to protect wild animals, predators have become more widespread again. As a result, farmers once more need to protect their livestock, and guard dogs are enjoying an unexpected revival.

A 几千年来，牧场护卫犬与牧羊人一起工作，保护羊、山羊和牛免受狼和熊等掠食者的袭击。然而，在19世纪和20世纪，当这些掠食者大多被消灭时，大多数护卫犬也失去了工作。然而近年来，随着保护野生动物的努力加强，掠食者再次变得更加广泛。结果，农民们再次需要保护自己的牲畜，而护卫大也因此意外地迎来了复兴。

BToday there are around 50 breeds of guard dogs on duty in various parts of the world. These dogs are raised from an early age with the animals they will be watching and eventually these animals become the dog's family. The dogs will place themselves between the livestock and any threat, barking loudly. If necessary, they will chase away predators, but often their mere presence is sufficient. 'Their initial training is to make them understand that livestock is going to be their life,' says Dan Macon, a shepherd with three guard dogs. 'A fluffy white puppy is fun to be around, but too much human affection makes it a great dog for guarding the front porch, rather than a great livestock guard dog.'

B 如今，世界各地大约有50个品种的护卫犬在值勤。这些犬从小与它们将要保护的动物一起抚养，最终这些动物成为它们的“家人”。这些大会将自己置于牲畜与任何威胁之间，大声吠叫。如有必要，它们会驱赶掠食者，但通常它们的存在就足够了。“它们的初步训练是让它们明白，牲畜将是它们的生活，“三只护卫犬的牧羊人丹·梅肯说道。”一只毛茸茸的白色小狗很好玩，但过多的人类宠爱会让它成为一个看守前廊的好狗，而不是一个优秀的护卫犬。

CThe evidence indicates that guard dogs are highly effective. For example, in Portugal, biologist Silvia Ribeiro has found that more than 90 per cent of the farmers participating in a programme to train and use guard dogs to protect their herds against attack from wolves rate the performance of the dogs as very good or excellent. In a study carried out in Australia by Linda van Bommel and Chris Johnson at the University of Tasmania, more than 65 per cent of herders reported that predation stopped completely after they got the dogs, and almost all the rest saw a decrease in attacks. 'If they are managed and used properly, livestock guard dogs are the most efficient control method that we have in terms of the amount of livestock that they save from predation,' says van Bommel.

C 证据表明，护卫大非常有效。例如，在葡萄牙生物学家西尔维娅·里贝罗发现，参加培训和使用护卫犬保护羊群免受狼攻击的农民中，有超过90%的人认为这些大的表现非常好或优秀。在澳大利亚，塔斯马尼亚大学的琳达·范·博梅尔和克里斯约翰逊进行的研究中，超过65%的牧人表示，在他们得到护卫大后，掠食行为完全停止，几乎所有其余的人也看到了攻击减少。“如果得到正确的管理和使用，护卫大是我们在保护牲畜免遭掠食方面最有效的控制手段，“范·博梅尔说道。

DBut today's guard dogs also have a new role – to help preserve the predators. It is hoped that reductions in livestock losses can make farmers more tolerant of predators and less likely to kill them. In Namibia, more than 90 per cent of cheetahs live outside protected areas, close to humans raising livestock. As a result, the cheetahs are often held responsible for animal losses, and large numbers have been killed by farmers. When guard dogs were introduced, more than 90 per cent of farmers reported a dramatic reduction in livestock losses, and said that as a result they were less likely to kill predators. Julie Young, at Utah State University in the US, believes this result applies widely. “There is common ground from the livestock perspective and from the conservation perspective,' she says. 'If ranchers don't have a dead cow, they will not make a call to apply for a permit to kill a wolf.”

D 但如今的护卫犬也有了新的角色--帮助保护掠食者。希望通过减少牲畜损失，可以让农民对掠食者更加宽容，减少杀害它们的可能性。在纳米比亚，超过90%的猎豹生活在没有保护区的地区，靠近养殖牲畜的农民。因此，猎豹经常被认为是牲畜损失的罪魁祸首，大量猎豹被农民杀害。当护卫大被引入后，超过90%的农民报告说，牲畜损失显著减少，表示因此他们更不愿意杀害掠食者。美国犹他州立大学的朱莉·杨认为，这一结果具有广泛适用性。“从牲畜的角度和保护的角度来看是有共同点的，“她说。“如果牧场主没有死牛，他们就不会申请杀狼的许可证。

ELooking at all the published evidence, Bethany Smith at Nottingham Trent University in the UK found that up to 88 per cent of farmers said they no longer killed predators after using dogs – but warned that such self-reported results must be taken with a pinch of salt. What's more, it is possible that livestock guard dogs merely displace predators to unprotected neighbouring properties, where their fate isn't recorded. 'In some regions, we work with almost every farmer, but in others only one or two have dogs,' says Ribeiro. 'If we are not working with everybody, we are transferring the wolf pressure to the neighbour's herd and he can use poison and kill an entire pack of wolves.'

E 查看所有已发布的证据后，英国诺丁汉特伦特大学的贝瑟尼·史密斯发现，88%的农民表示，在使用护卫犬后他们不再杀害掠食者--但她警告说，类似的自我报告结果必须谨慎对待。更重要的是，护卫犬可能仅仅是将掠食者转移到没有保护的邻近地产，这里它们的命运未被记录。“在一些地区，我们几乎和每个农民合作，但在其他地区只有一两个人使用狗，“里贝罗说道。“如果我们没有与每个人合作，我们就把狼的压力转移到了邻居的牧群上，而他可能会使用毒药，杀死整群狼。

FAnother concern is whether there may be unintended ecological effects of using guard dogs. Studies suggest that reducing deaths of one type of predator may have a negative impact on other species. The extent of this problem isn't known, but the consequences are clear in Namibia. Cheetahs aren't the only species that cause sheep and goat losses there: other predators also attack livestock. In 2015, researchers reported that in spite of the impact farmers obtaining guard dogs had on cheetahs, the number of jackals killed by dogs and people actually increased. Guard dogs have other ecological impacts too. They have been found to spread diseases to wild animals, including endangered Ethiopian wolves. They may also compete with other carnivores for food. And by creating a 'landscape of fear', their mere presence can influence the behaviour of prey animals.

F 另一个担忧是使用护卫犬可能带来的意外生态效应。研究表明，减少一种掠食者的死亡可能对其他物种产生负面影响。这一问题的程度尚不清楚，但其后果在纳米比亚是显而易见的。猎豹并不是唯一会造成羊和山羊损失的物种，其他掠食者也会攻击牲畜。2015年，研究人员报告称，尽管农民使用护卫大对猎豹产生了影响，但被狗和人杀死的豺狼数量实际上增加了。护卫犬也对生态环境产生了其他影响。研究发现，它们会把疾病传播给野生动物，包括濒危的埃塞俄比亚狼。它们还可能与其他食肉动物争夺食物。通过制造恐惧景观”，它们的存在本身就会影响猎物动物的行为。

GThe evidence so far, however, indicates that these consequences aren't always negative. Guard dogs can deliver unexpected benefits by protecting vulnerable wildlife from predators. For example, their presence has been found to protect birds which build their nests on the ground in fields, where foxes would normally raid them. Indeed, Australian researchers are now using dogs to enhance biodiversity and create refuges for species threatened by predation. So if we can get this right, there may be a bright future for guard dogs in promoting harmonious coexistence between humans and wildlife.

G 然而如今的证据表明，这些后果并不总是负面的。护卫犬通过保护脆弱的野生动物免受掠食者的攻击，反而带来了意想不到的好处。例如，它们的存在被发现能保护那些在田间建巢的地面鸟类，而这些鸟类通常会被狐狸袭击。事实上，澳大利亚的研究人员现在正在利用狗来增强生物多样性，并为那些受到掠食威胁的物种创造避难所。因此，如果我们能够做到这一点，护卫犬在促进人类与野生动物和谐共存方面可能有着光明的未来。