Mermaid’s purses are the protective cases in which the eggs of dogfish, skates, and rays are released into the environment. The rectangular purse is leathery and has long tendrils streaming from each corner. The tendrils anchor the case to seaweed or rocks and protect the embryos during the six to nine months it takes for them to hatch. Empty cases often wash up on beaches.
In a study of 570 shark attacks, it was found that most shark attacks occur near shore. These data are not surprising since most people who enter the water stay close to the shore.
| Distance from Shore |
Percentage of Shark Attacks |
Percentage of People Who Swim that Distance |
| 50 ft (15 m) |
31 |
39 |
| 100 ft (30 m) |
11 |
15 |
| 200 ft (60 m) |
9 |
12 |
| 300 ft (90 m) |
8 |
11 |
| 400 ft (120 m) |
2 |
2 |
| 500 ft (150 m) |
3 |
5 |
| 1,000 ft (300 m) |
6 |
9 |
| 1 mile (1.6 km) |
8 |
6 |
| 1.6 km) |
22 |
1 |
