The Smithsonian Tropical Research Institute (STRI) offers a free half-hour tour of its Bocas del Toros Research Station (tel. 757-9794, Panama City tel. 212-8564 or 212-8082, www.stri.org) on Thursday and Friday 3–5 p.m. Theoretically, anyway. Call ahead to confirm a time, as drop-ins occasionally get turned away, especially if a school group is touring the facility.

The station is on the narrow isthmus that separates Boca town from the rest of Isla Colón and contains laboratories, teaching facilities, and accommodations for researchers and visitors. During the tour, guests can see scientists at work on experiments and some of the specimens they have gathered, including an impressive collection of some of the 70 species of sponge found in the archipelago. There is also an aquarium that contains sea urchins, five types of starfish, sea cucumbers, coral, sea anemones, lobsters, and a green sea turtle.

The station is built right in the middle of what the scientists are studying, so the guide can, for instance, point out living examples of red, black, and white mangroves near the dock and the different species of caiman living in the brackish pond in front of the station. The tour is led by a friendly, enthusiastic former boatman who speaks Spanish and okay English.

Bring bug spray, as the chitras here can be brutal. The research station is a US$0.50–taxi ride from downtown.