Characterisation of sperm production and morphology in the male Philippine crocodile Crocodylus mindorensis via voluntary behavioural training
Shelley E. S. Sandmaier
A B , Teresa Shepard A , Andy Reeves A , Kaytlin Bohr A , Jessi Krebs A and Jason R. Herrick A
+ Author Affiliations
- Author Affiliations
A Omaha’s Henry Doorly Zoo and Aquarium, 3701 S. 10th Street, Omaha, NE 68107, USA.
B Corresponding author. Email: shelley.sandmaier@omahazoo.com
Reproduction, Fertility and Development 34(5) 410-416 https://doi.org/10.1071/RD21016
Submitted: 22 January 2021 Accepted: 10 July 2021 Published: 13 August 2021
Abstract
Philippine crocodiles Crocodylus mindorensis are critically endangered due to agricultural and fishing threats that have severely fragmented their habitat and population in the Philippines. Captive management plans are important to safeguard against their extinction, but the current population in US zoos is small, and breeding is hampered by the slow growth of this species and the danger of introducing differently sized animals for breeding. There is little information regarding the sperm characteristics of crocodilians, and none for Philippine crocodiles. In this study, we sought to characterise sperm production in the male Philippine crocodile (n = 1) by performing voluntary (without sedation or restraint) collections (n = 181) over a 3.5-year period. Peak sperm production in this individual occurs from January to July, when the mean (±s.e.m.) total number of spermatozoa recovered was 10.2 × 106 ± 3.8 × 106 (n = 104), compared with 0.3 × 106 ± 0.2 × 106 (n = 71) for all other months of the year. Analysis of sperm morphology indicated that 15.9% of spermatozoa exhibited normal morphology. A bent tail was the most common abnormality (48.2%) observed. Understanding the basic reproductive biology of the male Philippine crocodile will facilitate the development of artificial reproductive technologies to improve captive propagation and genetic management of this species.
Keywords: assisted reproductive technology, fertility, reproduction, reptiles, spermatozoa.
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