he's the director of the smithsonian tropical research institute here. he loves to point out the incredible diversity in panama. for scientists, this is a dream location. >> what makes panama a unique place to study the environment? this is a remarkable place. because we have a very narrow ismis here- 50 mi at the narrowest point so we can get to either ocean the pacific or the atlantic in a matter of an hour. >> we spoke with matt at the smithsonian's nature center at culebra point, a narrow strip of land that juts straight into the ocean. ships were passing by, the sun was heading down for the night. it was time to get down to business. >> i understand there are sloths here? >> yes. >> can we go take a look? >> yes, let's go take a look they are very handsome. >> turns out sloths aren't the most outgoing animals. we had a bit of scanning of treetops to do. and then, we saw our first signs of life. >> there's one. oh yeah. oh there's another sloth right there. >> he's just mooning you now. >> this is apparently prime time for sloths. and while the first