Photographs of capybaras relaxing next to crocodiles and caimans continue making the rounds on the Internet, and these pictures aren’t fabricated in any way. Scientists who have been studying the rodents for years have offered clues about why such encounters can happen, from predator economics and the capybara’s defenses to studies on how these animals respond to predation risks.
Their Iberá counterparts ranged farther from water and adjusted their activity around weather conditions rather than an immediate threat. Avila and her co-authors concluded that living near big cats pushes capybaras to manage risk across both location and timing, and that restoring predators to a landscape can reshape more than prey behavior, potentially extending to vegetation and soil over time. Research on capybara ecology provides useful context for understanding why some encounters between capybaras and caimans may remain peaceful. Researchers who study capybara ecology frame this as ordinary risk-versus-reward math, the kind most predators are less likely to attack when the potential cost is high relative to the nutritional benefit. Capybaras also have defenses that cost them little: living in groups in which individuals can share vigilance, and swimming with their eyes, ears, and nostrils positioned high on the head so they can remain mostly submerged while still tracking movement nearby. Put the size, group living, and quick escape into deep water together, and a healthy adult capybara may be a less attractive target for a caiman than smaller or less risky prey.
The same group returned to the subject in 2025 with a paper in Behavioral Ecology and Sociobiology , this time tracking where and when capybaras chose to forage instead of just how alert they stayed. The study used observations from Iberá collected before jaguars were reintroduced there in 2021, allowing the researchers to compare those conditions with capybaras living under predator pressure in the Pantanal. Adult capybaras can weigh more than 100 pounds and carry thick hides plus sharp incisors capable of causing injury, so attacking one can carry a cost for a caiman, especially when fish and other easier prey are available nearby.
Pantanal capybaras stayed in relatively close groups, grazed near water, and stuck to daylight hours across different temperature and moon-phase conditions, according to the study.
