The vertebrate extinction rate over the past century is approximately 22-100 times greater than background extinction rates [1], and large mammals are particularly at risk [2, 3]. Quaternary megafaunal extinctions have been attributed to climate change [4], overexploitation [5], or a combination of the two [6]. Rhinoceroses (Family: Rhinocerotidae) have a rich fossil history replete with iconic examples of climate-induced extinctions [7], but current pressures threaten to eliminate this group entirely. The Sumatran rhinoceros (Dicerorhinus sumatrensis) is among the most imperiled mammals on earth. The 2011 population was estimated at ≤216 wild individuals [8], and currently the species is extirpated, or nearly so, throughout the majority of its former range [8-12]. Understanding demographic history is important in placing current population status into a broader ecological and evolutionary context. Analysis of the Sumatran rhinoceros genome reveals extreme changes in effective population size throughout the Pleistocene. Population expansion during the early to middle Pleistocene was followed by decline. Ecological niche modeling indicated that changing climate most likely played a role in the decline of the Sumatran rhinoceros, as less suitable habitat on an emergent Sundaland corridor isolated Sumatran rhinoceros populations. By the end of the Pleistocene, the Sundaland corridor was submerged, and populations were fragmented and consequently reduced to low Holocene levels from which they would never recover. Past events denuded the Sumatran rhinoceros of genetic diversity through population decline, fragmentation, or some combination of the two and most likely made the species even more susceptible to later exploitation and habitat loss. VIDEO ABSTRACT.

A cooperative method was developed for collecting semen from a Magellanic penguin. Ejaculate parameters and semen production during a breeding season were characterized. Experiments were performed to study the effect on penguin spermatozoa of two temperatures (4°C and 21°C) for short-term storage, and two cryoprotectants (dimethylsulfoxide [DMSO] and ethylene glycol [EG]) for long-term storage (cryopreservation). All dilutions were made using modified Beltsville Poultry Semen Extender. Sperm quality was assessed by evaluating motility and forward progression (sperm motility index [SMI]), viability, and morphology. A total of 39 ejaculates was collected over the 40-day study period. Thirty-eight ejaculates contained spermatozoa, but semen quality decreased toward the end of the study period. Varying levels of urate contamination were present in all ejaculates. Sperm quality parameters were similar for diluted samples held at 4°C and 21°C, and samples maintained high numbers of viable (77.8 ± 5.4%) and morphologically normal (67.9 ± 2.5%) spermatozoa at 3 hr. SMI and percentage of viable sperm decreased (P < 0.05) and the number of spermatozoa with a bent head or midpiece increased (P < 0.05) for both temperature groups over the 3-hr storage interval. DMSO and EG were equally effective in maintaining penguin sperm quality parameters during the cryopreservation and thawing process. Frozen-thawed semen maintained 69 ± 5 and 78 ± 3% of its pre-freeze SMI and viability, respectively. SMI and viability decreased slightly during the cooling and equilibration phases but remained relatively stable during the 3-hr storage interval post-thaw. Frozen-thawed semen also exhibited an increase (P < 0.05) in spermatozoa with a bent head or midpiece over time. The pre-freeze SMI was higher (P < 0.05) for ejaculates with low levels of urates (clean ejaculates) compared with ejaculates with high levels of urate contamination, but sperm viability and morphology were similar (P > 0.05). Both SMI and viability of frozen-thawed spermatozoa were higher (P < 0.05) for clean than for contaminated ejaculates. This is the first report on penguin ejaculate parameters, semen production, and preliminary methods for short-and long-term semen storage.

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New World parrots are declining throughout their range. Blue and Gold Macaw Ara ararauna was extirpated from the island of Trinidad in the late 1960s through anthropogenic processes. The Cincinnati Zoo & Botanical Garden is assisting the Wildlife Section of the Forestry Division, Trinidad on a mission to restore the species into its historical range within the Bush-Bush Sanctuary in the Nariva Swamp. The Sanctuary has been protected by the government of Trinidad and is the home of the endangered Red-bellied Macaw Ara manilata and West Indian Manatee Trichechus manatus. Zoo and Wildlife personnel participated in three separate releases, beginning in December 1999 through to March 2000. The initial release consisted of an identical sex group of macaws followed by two additional releases of pairs/groups of birds. Of 18 Blue and Gold Macaws, 14 were released into the Nariva Swamp and are currently being monitored by the Wildlife Section, Zoo personnel and surrounding community. Translocation of wild populations of parrots has proven to be a viable solution to restocking wild populations that have been regionally extirpated.

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