Puma (Puma concolor) modifications on medium-sized mammals: Can its taphonomic signature be differentiated from other South American carnivores?

1. What they did

Archaeologists in the Argentine Pampas want to know how much carnivores, as well as people, shaped the bone remains found at ancient sites. To build a reference for the puma, the authors fed ten dead European rabbits, two a day for five days, to two adult male pumas kept at La Máxima Biopark in Olavarría. The rabbit stands in for native medium-sized prey such as plains vizcacha, armadillos and mara.

They collected all the bones the pumas left, measured and identified every piece, and examined each under a microscope for fractures and tooth marks. They measured the punctures, then compared the results with earlier, similar experiments with captive Pampas foxes and Geoffroy’s cats.

2. What they found

• The pumas left 514 bone pieces, 87% identifiable, from at least five of the ten rabbits. Pieces were 3.2 to 85.0 mm long (mean 16.2 mm).
• Skulls, tibiae, metatarsals, astragali and calcanei were most common. The scapula, humerus and patella were missing entirely, and vertebrae, ribs and the forelimb were scarce, so the pumas probably swallowed those smaller, less dense bones.
• 54% of the pieces showed carnivore damage: 51% were fractured, mostly irregularly, and 14% carried tooth marks. Pits were the most frequent mark, then scores and punctures; crenulated edges were also common.
• Of 28 punctures, 22 could be measured: mean maximum length 3.6 mm, median 3 mm, range 1.9 to 8.4 mm.
• Compared with the fox and the wild cat, the pumas left the fewest pieces, ate the forelimbs and sometimes the pelvis, and left pieces with a significantly greater median length. Their punctures were larger, though not significantly, and reached sizes the smaller carnivores never made.

3. What they concluded

On medium-sized prey, the bones a puma leaves are dominated by the skull and the lower limb bones, especially of the hindlimb, and are highly fragmented with many tooth marks. The signatures of puma, Pampas fox and Geoffroy’s cat are very similar, so no single feature yet separates them; prey size probably explains much of this. The authors call for studies of ingested remains, pit measurements and wild pumas, since captive animals may chew bones more than wild ones.

7. Implications for conservation (from the paper)

• Recognizing puma damage on bones can show where pumas lived in the past and what they ate, which helps in understanding their former range in the Pampas, where they were extirpated and are now returning.