CAPE CANAVERAL. Florida. May 4: Exhausted from a two-week flight that killed many of the animals on board. Columbia's astronauts said the casualty rate would have been higher if they hadn't set up an intensive care unit, reports AP.

As It was, 55 of 96 baby rats came back dead, victims of maternal neglect.

"When you initially see this, you say. Oh, no!" Then we started treating. I guess the veterinarian in me kicked in." Richard Linnehan said late Sunday after the space shuttle landed, ending a 16-day mission that was the most in-depth study ever into how the brain operates in space.

Scientists want that question answered before planning possible moon colonies or a trip to Mars. Linnehan said the mission also provided immediate lessons for the international space station, to be as-

sembled in orbit beginning this year.

The mortality rate was even higher among the young swordtail fish that flew on the mission: 200 dead out of 225. most likely because their water was too warm. But the astronauts didn't learn about that until after they landed; they didn't have access to the fish in orbit.

They did have access to the rats, however, and did everything in their power to save tfie tiny, emaciated rodents once it became clear they were quickly dying of dehydration.

The astronauts were also hustled off Columbia. Six of the seven crew members left on stretchers; doctors wanted them reclining to preserve the lingering effects of their weightlessness. Ten hours later, they were still undergoing medical exams: the tests were expected to go on for days.