The family Corivdae, which includes crows and ravens, contains arguably some of the most intelligent species the animal kingdom has to offer. Separated from primates by at least 252 million years of evolution, birds bear striking physiological differences from mammals, while displaying similar intellectual abilities. This apparent convergent evolution of intelligence sheds light on what could possibly be a universal phenomenon. While many excellent studies show the abilities of corvids, the majority of them test only captive subjects. This study tested the capabilities of both captive and wild ravens, from three different species. The first portion of the study tested which of the four solutions offered wild ravens would choose when solving a Multi-Access Box. The second portion of the study tested the performance of wild and captive ravens when solving a Multi-Latch Box. The nine raven subjects were split into four different levels of enculturation based on their known histories. Two wild common ravens (Corvus corax) on the campus of the University of Arizona were level 1, four wild common ravens in the parking lot of a United States Forest Service parking lot were level 2, two captive and trained Chihuahuan ravens (Corvus cryptoleucus) from the Raptor Free Flight program at the Arizona-Sonora Desert Museum comprised level 3, and one captive and trained white-necked raven (Corvus albicollis) made level 4. It is possible to run trials with completely wild and free birds. It was found that ravens prefer direct methods of obtaining food, such as opening doors and pulling strings, instead of tool use. It was also found that while the relationship between enculturation level and success solving a puzzle was not linear, captive birds were the best solvers. The data given here suggest that captivity, training and enrichment history, and enculturation should all be considered when performing cognitive studies with animals.

Doctor of Philosophy / Department of Psychological Sciences / Jerome Frieman / Spotted hyenas (Crocuta crocuta) live in highly-complex, female-dominated groups called “clans.” Due to their social arrangement, spotted hyenas were a logical species on which to test the social complexity hypothesis. In the present study, they were presented with a series of puzzle boxes designed to test problem-solving behavior. The five puzzles varied in difficulty. All spotted hyenas solved the puzzle with the lowest difficulty level, five out of six solved the medium puzzles at least once, and one out of six solved the high difficulty puzzle. Some decreases in behavior diversity and time working on the puzzles were observed over successful trials; however, the decreases were only significant for successful trials of one medium-level puzzle. Decreases in work time were observed for some unsuccessful trials and the decrease was statistically significant for the highest difficulty puzzle. Overall, spotted hyenas were proficient at problem solving in the present study. Social learning is an important component of a lengthy juvenile period for spotted hyenas, and they have also been shown to influence one another’s feeding behavior. Furthermore, spotted hyenas participate in scramble competition when feeding and forage for and hoard food. In light of these behaviors, social learning was examined using the social transmission of a flavor preference (STFP) procedure. STFP was not observed overall. The sex of the subjects did not significantly influence the results; however, subjects that interacted with each other longer were significantly more likely to show STFP. The STFP procedure may not be sensitive enough to detect social learning in spotted hyenas. Perhaps spotted hyenas have no need to learn STFP due to their digestive and/or immune systems. The results of the current experiments make important contributions to existing knowledge. Data from other species like spotted hyenas are vital for evaluating the generality of the social complexity hypothesis since support thus far has come from data on primates. This study was the first to investigate STFP in a species from the Feliformia suborder. Additionally, finding more evidence that spotted hyenas have advanced cognitive abilities is essential for researchers and zoo personnel who work with spotted hyenas in captivity.