Tar-Pit Bones Show Ailments of Extinct Cats

Times Staff Writer

Scientists at the La Brea tar pits are studying the illnesses and injuries that plagued a creature extinct for at least 10,000 years.

Staff and volunteer paleopathologists at the George C. Page Museum are cataloguing the ills that the saber-toothed cat fell prey to. Knowing what went wrong with the long-vanished cats, incorrectly called tigers by earlier researchers, has no obvious utility. But it provides intriguing clues to how they lived in sickness and in health.

The Page Museum in Hancock Park houses the fossils of countless animals and plants that were trapped in the area's tar pits, vast deposits of asphalt that continues to seep to the surface and scent the park. Between 10,000 and 40,000 years ago, giant mammoths, dire wolves and hundreds of other Ice Age species were trapped in the asphalt deposits like flies on flypaper. Their remains, preserved by the substance that killed them, constitute one of the greatest caches of Ice Age fossils in the world.

5,000 Injured Bones

Fred P. Heald, 75, a retired surgeon who lives in Palos Verdes Estates, assumed the daunting task of putting the museum's 75-year-old collection of diseased and traumatized bones in order.

"Paleopathology," the volunteer explained, "is the study of diseases and injuries present in fossil specimens." Among the 500,000 specimens in the museum's vast ossuary are some 5,000 saber-toothed cat bones that show evidence of everything from arthritis to infection with the fungus that causes Valley fever to a half-broken neck. (The pathology collection includes 4,000 dire wolf bones as well.)

"I started out at one end of the collection and worked clear through, bone by bone," recalled Heald, who jotted his description and diagnosis of each specimen on an index card.

Heald learned about Smilodon californicus , as the saber-tooth is properly called, as he went along. "Nobody has ever written a textbook on the anatomy and pathology of a Smilodon cat," he said, "but, fortunately, all animals are hooked up pretty much the same way."

Heald was delighted to discover that, anatomically at least, the saber-tooth responded to illness and injury much as humans do. Working with museum staffer Christopher A. Shaw, who is interested in the relationship of physical form to function, Heald can make intelligent guesses about how the cats brought down their prey and even about their social organization.

Social Animal

"I sat for four or five hours a day, just writing down what I saw," Heald recalled. "Out of the trees came a little better view of the forest."

The scientists are convinced by the asphalt-blackened bones that the saber-toothed cat was a social animal that hunted with others in a pack or pride. As Heald explained, the bones show evidence of wounds, fractures and dislocations disabling enough to have caused death if the animal had been a solitary hunter.

But from clues such as broken sabers worn smooth over time, the scientists know that even some cats that had lost their characteristic canine teeth lived with their disabilities for a considerable period before their sticky demise in the tar pits. No longer able to kill for themselves, the cats probably lived on the scraps of kills made by others in the group, the men speculate.

Shaw noted that a modern observer can't help but wince at some of the maladies reflected in the collection, such as a hip that shows evidence of a massive infection, which must have caused the animal considerable pain. "I sit there and think, 'How did this guy get around?' "

Pathological or not, the museum's bones are remarkably eloquent. Page Museum staffer Antonia Tejada-Flores found evidence that the saber-tooth roared when she came across a cigar box full of fossilized throat bones called hyoids. The hyoids of the saber-tooth had relatively elastic connections, similar to those of contemporary cats that roar. Non-roaring cats have relatively inflexible ones.

Former museum staffer William A. Akersten found other bones to bolster his theory that the cats used their sabers, not primarily to stab or slash, but to execute a calamitous shearing bite to soft parts of their prey, which then bled to death or died of shock.

As Shaw pointed out, the saber-toothed cat is an especially intriguing animal "because there's nothing like them around today. It's fascinating to see what made them go."

On the basis of their bones, the scientists believe the cat was a stealth hunter. "It's not a fast animal like a cheetah," said the 37-year-old Shaw, a Granada Hills resident who is the museum's curator of collections. "The tail is the biggest clue. Animals that run down their prey generally have a large tail for balance. The Smilodon had a very short tail."

In a scientific paper, Heald praised bone as an expressive medium. "Living bone," he wrote, "is not a hard, unyielding material that holds animals together. Bone is dynamic, it responds to use and especially to misuse. It has quite set ways of growing and of healing itself after injury which are common to all animals."

Heald explained that when an animal's muscles are stressed, little tears occur. There is bleeding, and then telltale calluses form on the bone. Many of the cats in the collection sustained terrible, repeated stress injuries to their necks and backs that cause the scientists to speculate that the saber-tooths leaped on large prey with great force.

The discovery in a Texas cave of another kind of saber-tooth surrounded by the bones of young mastodons and mammoths leads the men to believe juvenile elephants were probably a Smilodon foodstuff. Without the cats, Heald theorized, "the world would have been clear up to its eyes in elephants."

Take Lions

The scientists sometimes use what they know about living animals to theorize about the vanished ones. "Lions are noteworthy," Shaw said, "because they are the only species nowadays that will attack something larger than themselves."

The lions' willingness to attack larger animals is not without hazards. But lions are often able to live with the crushed paws and other injuries that large prey can inflict on predators because the pride allows wounded members to feed.

Heald speculates that the shoulder wounds many saber-toothed cats sustained may have been inflicted by other cats while feeding. "Watch lions," he said. "When eating, they bite each other, but when they are finished and satisfied, they lick the blood off each other." Heald has found it difficult to get non-anectodal information about the pathology of modern lions living in the wild. As experts told him, "there are no autopsies done on lions in the Serengeti."

Shaw, Heald and others using the paleopathology collection are aware that, however logical their theories about what the saber-tooth did, no one will ever know for sure if they are right.

Until recently, Shaw noted, the museum staff thought the saber-tooth's largest front toe was probably toward the middle of its paw, like a modern lion's. But the recent find of an almost complete saber-tooth skeleton in the tar pits, with its bones in place, reveals that the big toes were across from each other on the inside of the paws--in the same position as human big toes.

As Shaw said, "We're learning new things all the time."

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