In a two-choice object test using different sensory stimuli, both female African savanna elephants showed more interest for stimuli from former keepers (no interaction for up to 13 years) than for stimuli from unfamiliar persons.

Distribution of serum ferritin values (ng/mL) in black (Diceros bicornis) rhinoceros samples (n = 222) in relationship to health classification as determined by serum amyloid A (clinically healthy [< 1 mg/L SAA]; subclinical [1–7 mg/L SAA]; clinically abnormal [> 7 mg/L SAA]).

Amphibian conservation efforts are limited by a lack of knowledge about their life history traits. At a conservation breeding facility in Andasibe, Madagascar, we observed diverse breeding patterns and egg numbers among 11 frog species, revealing links between reproductive strategies and environmental factors. These findings provide valuable data for assessing threats to related species and informing conservation in a biodiversity hotspot.

Overview of two-way factorial experiment to evaluate how ambassador animals impact the educational outcomes of a zoo exhibit. Subjects were given a survey assessing attitudes toward exotic pets and knowledge of conservation before or after visiting the exhibit, with or without an animal present. Upon exiting the exhibit, subjects demonstrated higher conservation knowledge and less willingness to own exotic pets regardless of whether they experienced an ambassador demonstration: no impact of ambassador animals was detected.

A secretarybird and a life table for the ESB secretarybird population.

More mature first-generation breeding Ozark hellbenders at the Saint Louis Zoo oviposit earlier and have eggs that develop longer and hatch later than the less mature second-generation Ozark hellbenders, which are the offspring of the first-generation and were reared at the Zoo to sexual maturity. Ozark hellbender embryos are also pictured.

The long-term growth of Ozark hellbenders raised at the Saint Louis Zoo differ by river of origin (EPR, CR, and NFR, as Eleven Point River, Current River, and North Fork of the White River, respectively) in accordance with observations from wild populations and genetic relatedness.

The ovary of a 50-year-old orangutan showing no active follicles (left) in comparison to the ovary of a stillborn female infant (right).

This study demonstrates the efficacy of diver-operated stereo-video equipment in accurately collecting biometric data from a diverse range of elasmobranch and teleost fish species within a single diving session in aquariums.

Estrogen and glucocorticoid concentrations trended together in a female clouded leopard.