Study Shows Unusual Evolutionary Changes in African Wild Dogs
2020-09-14
LRC
TXT
大字
小字
滚动
全页
1A study of the African wild dog has identified unusual physical changes that support the animal's ability to run for long periods while hunting prey.
2The African wild dog is native to southern and eastern Africa.
3It differs from other predators - such as lions and hyenas - because it uses an unusual hunting method.
4The animal chases its prey over long distances until the target gets so tired it collapses.
5Other animals depend on different hunting skills to catch prey, including speed, strength and quiet, secret movements.
6A new study of this endangered animal has identified important changes that happened over time that permit the African wild dog to hunt this way.
7The African wild dog is the only dog-like animal that has only four digits on the front paws.
8Scientists say having only four full toes supports increased speed and longer jumps.
9The new research identifies a small, hidden first digit under the skin of the front feet, or paws.
10The discovery was made through computer imaging methods and an examination of an African wild dog that died of natural causes at an animal park.
11The muscles related to this digit have been re-formed and are used to help with "proprioception" - the body's awareness of its position and movement.
12The researchers also saw expansions in limb muscles containing nerve tissue thought to resist tiredness.
13They also identified tissue material on the front paw that may help launch the dogs forward.
14In addition, the team observed a reduction in muscles that normally act to turn the wrist and forearm, possibly demonstrating an increased demand for stability.
15Groups of 20 to 30 African wild dogs often hunt together in search of prey.
16They can travel up to 50 kilometers a day.
17The animals have been recorded running at least 64 kilometers an hour for up to an hour during a hunt.
18Heather Smith is a researcher at Midwestern University in Glendale, Arizona.
19Her team completed a study on the findings.
20The study recently appeared in the publication PeerJ.
21Smith told the Reuters news agency, "They're very effective hunters, with up to 60 percent of hunts ending in successful kills."
22She noted that is higher than lions, at 30 percent, and hyenas, at 25-30 percent.
23Smith said African wild dogs are clearly built for stamina - having strength that lets you continue to do something for a long time.
24That makes them different from other predators that use explosive speed, strength and stealth.
25"However, African wild dogs sometimes lose their kills to these larger, more aggressive carnivores," she said.
26I'm Bryan Lynn.
1A study of the African wild dog has identified unusual physical changes that support the animal's ability to run for long periods while hunting prey. 2The African wild dog is native to southern and eastern Africa. It differs from other predators - such as lions and hyenas - because it uses an unusual hunting method. The animal chases its prey over long distances until the target gets so tired it collapses. Other animals depend on different hunting skills to catch prey, including speed, strength and quiet, secret movements. 3A new study of this endangered animal has identified important changes that happened over time that permit the African wild dog to hunt this way. 4The African wild dog is the only dog-like animal that has only four digits on the front paws. Scientists say having only four full toes supports increased speed and longer jumps. 5The new research identifies a small, hidden first digit under the skin of the front feet, or paws. The discovery was made through computer imaging methods and an examination of an African wild dog that died of natural causes at an animal park. 6The muscles related to this digit have been re-formed and are used to help with "proprioception" - the body's awareness of its position and movement. 7The researchers also saw expansions in limb muscles containing nerve tissue thought to resist tiredness. They also identified tissue material on the front paw that may help launch the dogs forward. In addition, the team observed a reduction in muscles that normally act to turn the wrist and forearm, possibly demonstrating an increased demand for stability. 8Groups of 20 to 30 African wild dogs often hunt together in search of prey. They can travel up to 50 kilometers a day. The animals have been recorded running at least 64 kilometers an hour for up to an hour during a hunt. 9Heather Smith is a researcher at Midwestern University in Glendale, Arizona. Her team completed a study on the findings. The study recently appeared in the publication PeerJ. 10Smith told the Reuters news agency, "They're very effective hunters, with up to 60 percent of hunts ending in successful kills." She noted that is higher than lions, at 30 percent, and hyenas, at 25-30 percent. 11Smith said African wild dogs are clearly built for stamina - having strength that lets you continue to do something for a long time. That makes them different from other predators that use explosive speed, strength and stealth. 12"However, African wild dogs sometimes lose their kills to these larger, more aggressive carnivores," she said. 13I'm Bryan Lynn. 14Reuters reported on this story. Bryan Lynn adapted the report for VOA Learning English, with additional information from Midwestern University. Ashley Thompson was the editor. 15We want to hear from you. Write to us in the Comments section, and visit our Facebook page. 16________________________________________________________________ 17Words in This Story 18prey - n. an animal that is hunted or killed by another animal for food 19predator - n. animal that hunts and kills other animals for food 20endangered - adj. in danger of being lost 21digit - n. a finger, thumb or toe 22awareness - n. the knowledge that something exists 23limb - n. an arm or leg of a person or animal 24stability - n. a situation in which something is not likely to move or change 25stealth - n. movement that is quiet and careful in order not to be seen or heard 26carnivore - n. an animal that eats meat