Sawfish 'virgin births' astonish science

　　野生锯鳐单性繁殖

双语：佛罗里达州锯鳐能够单性繁殖后代

　　研究人员首次发现了一种生活在佛罗里达州河口的 锯 鳐 能够单性繁殖后代。人们推测这是此类物种的一种生存机制。此发现被刊登在《当代生物学》杂志上。以下是 Jonathan Webb 的报道。

　　Despite growing up to 12 feet in length with a vicious-looking snout, the smalltooth sawfish is critically endangered. Researchers from Stony Brook University in New York were doing a survey of the creatures to check on their genetic diversity。

　　They were surprised to find seven female fish that had no sign of a genetic father. They were all daughters of a virgin birth or parthenogenesis – this bizarre mechanism in which embryo grows from an unfertilised egg may be more common than scientists thought。

　　In captivity, sharks, reptiles and turkeys have all been known to surprise zookeepers and farmers with virgin births. But these fish are the first vertebrate virgin offspring ever found in the wild。

　　Questions

　　1. How did the scientists find out there was something different about these fish?

　　2. What sex are these special fish?

　　3. True or false? Virgin births are something scientists have come across before。

　　4. Which words are used to describe animals kept in a farm, a lab or a zoo?

　　Vocabulary and definitions

　　snout

　　大长鼻

　　critically endangered

　　极度濒危的

　　genetic diversity

　　遗传多样性

　　virgin birth

　　单性生殖

　　bizarre

　　离奇的

　　unfertilised egg

　　未受精的卵子

　　vertebrate

　　脊椎动物

　　offspring

　　后代

　　Answers to the questions:

　　1. How did the scientists find out there was something different about these fish? Answer: They were doing a survey on the creatures' genetic diversity。

　　2. What sex are these special fish? Answer: They are all females。

　　3. True or false? Virgin births are something scientists have come across before。

　　Answer: True. It has happened to sharks, reptiles and turkeys。

　　4. Which words are used to describe animals kept in a farm, a lab or a zoo? Answer: Animals kept in captivity。