A variety of mammals are known to visit BCI by swimming on (and off) the island. Jaguars and pumas, who need larger territories than the island’s size, are the most famous of these temporary visitors. One of the least expected species to find taking a dip in the canal is the Northern Tamandua (Tamandua mexicana). These anteaters are good climbers but are clumsy on the ground, and presumably even less well-off in the water. Although swimming has been documented for a number of their Xenarthran relatives (sloths, giant anteaters and some armadillos), the literature suggests that tamanduas avoid the water. However, when Helen Esser and Yorick Liefting were on their way in a boat to collect the island’s most beloved animals (ticks), they caught something completely different: a swimming tamandua!
Helen and Yorick were just about to cross the small channel between BCI and the Buena Vista peninsula, when they noticed a small head emerging from the water at about 2 meters from the boat. They quickly turned around to have a closer look and indeed, it was an adult tamandua crossing the canal. At that point, he must have been swimming for at least 120 m, and the island was still another 280 m away (Fig. 1). Although the anteater’s body was completely submerged, with only its long snout above the water, it did not seem to be having difficulties and looked as though it was comfortable in the water. Furthermore, its choice of crossing the canal at a very narrow point suggests that he may have even had knowledge of the topography, possibly from previous experience.
Still, crossing one of the world’s busiest shipping routes might not be the safest idea and Yorick and Helen soon realized that the anteater would certainly be hit or at least drown in the massive wake of an oncoming tanker ship. They therefore decided to put the animal into the boat so they could drive it across the channel. The anteater was happy to oblige, and immediately grasped onto one of the extended paddles and climbed into the boat. For the first few minutes it was just sitting there quietly, probably taking a breath. Soon however, he decided to inspect the boat more thoroughly – the steering wheel in particular – and Helen had to use a paddle to keep it at distance from Yorick, who was driving the boat. The result was a typical tamandua-defense display, after which the anteater decided to leave the scene and jump back into the water. Since the tanker ship was still passing, Helen grabbed the anteater’s tail and dragged it back into the boat, something he wasn’t too happy about… Thereafter the anteater tried to jump out of the boat several times and was eventually successful. He immediately oriented towards BCI, swimming the last 50 m to the shore in a straight line.
A captured tamandua would have been a nice surprise for Danielle Brown, who needed to tag anteaters with a GPS for her PhD project on movement patterns of Northern Tamanduas at BCI. Nevertheless, Danielle was happy to hear about the tamandua adventure as it might explain why at one point, her GPS showed the location of one of the transmitters to be in the canal. She almost falsely accused a crocodile of eating her research-subject but the anteater might as well have been crossing the canal. She argues that even though we cannot be certain that the anteater would have made it across the canal without assistance, it is very likely that other crossing points exist and that there is regular exchange between populations of tamanduas living on the mainland and the island, reducing the genetic isolation of the island population. If a willingness to take to water is widespread in Tamandua anteaters, it helps to explain the broad distribution of these species and suggests an ability to locate isolated patches of habitat in areas that have been modified by canals, dams, or rivers.
More details about this encounter can be found in the following publication
H. Esser, D. Brown, Y. Liefting (2010) “Swimming in the Northern Tamandua (Tamandua mexicana) in Panama” Edentata no. 11: 70-72