These tiny marsupials drop dead after 'extreme mating,' researchers report

SYDNEY, Australia - A tiny marsupial found only in northwest Australia mates so intensely that an entire generation of males can die off during a single breeding season, researchers reported on Friday. Biologists studying kalutas -- a mouse-sized marsupial found in the arid Pilbara region -- believe they die en masse because of sex-driven immune system collapse. Female kalutas mate frequently and with different males during each breeding season. "That means that males also have to mate a lot, an