Wildcard:
Only some sharks do, many lay eggs.
yeah, most sharks give birth to live young, but some release eggs that hatch later....
from Wikipedia:
* Oviparity - Some sharks lay eggs. In most of these species, the developing embryo is protected by an egg case with the consistency of leather. Some of these cases are corkscrewed into crevices for protection. Oviparous sharks include the horn shark and the swell shark.
* Viviparity - These sharks actually maintain a placental link to the developing young, more analogous to mammals than other fishes.
The young are born alive and fully functional. Hammerheads, the requiem sharks (like the bull and tiger sharks), the basking shark and the smooth dogfishes fall into this category. The blue shark produces the most young of sharks that have had the number of pups recorded, the maximum reported being 82.
* Ovoviviparity -
Most sharks utilize this method. The young are nourished by the yolk of their egg and by fluids secreted by glands in the walls of the oviduct. The eggs hatch within the oviduct, and the young continue to be nourished by the remnants of the yolk and the oviduct's fluids.
As in viviparity, the young are born alive and fully functional. Sometimes they are functional even before being born, as some species practice oophagy, where the first to hatch eat the remaining eggs in the oviduct. Sand tigers, makos, threshers, porbeagles and possibly great whites have oophagous young. The survival strategy for the species that do this is that the young are able to grow to an even larger size before being born. The whale shark is now considered to be in this category after having been classified as oviparous for a long time. Whale shark eggs found are now thought to have been aborted.
