Science Digest: What are the common disorders and causes of mortality in chelonia under primary veterinary care?

12 June 2025

Despite Chelonia species – tortoises, terrapins and turtles – being the eighth most common group of companion animals in the UK, with almost 2% of households owning at least one tortoise or terrapin, there is very little evidence on the most common disorders of pet chelonia. New research has given novel insights into the typical caseloads of chelonia seen by clinicians in general practice.

The new study, carried out by researchers at the Royal Veterinary College and published in PLOS One, is the largest to date to report the species, disorders and mortality within chelonia under primary veterinary care1. A random sample of 2,040 chelonia at primary care clinics participating in the VetCompass Programme during 2019 were reviewed, and data on species, recorded disorders and mortality extracted.

Of the sample, 94% of animals were recorded as tortoises, 4% as terrapins and 2% as turtles. Over half of the records didn’t have the species recorded, but of those that did, the most common tortoise species were Hermann’s tortoise (15%), Horsfield’s (13%) and Mediterranean spur-thighed tortoise (8%), and the most common terrapin species were musk turtle (0.8%) and yellowbelly slider (0.4%).

The majority of chelonia (78%) had at least one recorded disorder, the most common being beak abnormality (17% prevalence), overgrown nails (11%), shell abnormalities (10%), and anorexia (4%). These are often linked to inappropriate husbandry. Other disorders of note were plastron abnormality in terrapins (8%) and vitamin A deficiency in turtles (9%).

Cause of death was only recorded in just over half of records (55.45%). The most common recorded causes of death for tortoises were dog bites and cloacal prolapse (4%), and for terrapins, it was anorexia (13%) and coelomic mass (9%). The median age at death was young at 7.32 years, which the authors describe as concerning, although this may reflect young animals that are presented for veterinary care, and the true age may be higher, if owners don’t present their older tortoises for care.

A key limitation of the study is the limited clinical work-ups undertaken for chelonia under primary veterinary care, resulting in many final diagnoses being poorly specific, and the short temporal window within the clinical records.

The study highlights several key recommendations:

  • Ensure primary care veterinarians are well equipped to recognise the most commonly encountered chelonia species and how to identify, diagnose and treat their disorders.
  • Prioritise veterinary education on chelonian species identification and sex, to increase clinical confidence in recognising these patients.
  • Prioritise husbandry education on the most frequently encountered species – Hermann’s tortoise, Horsfield’s tortoise, Mediterranean spur-thighed tortoise, musk turtles and yellowbelly sliders. This should include how to reduce trauma from dog bites – the second leading cause of mortality.
  • Conduct further research into the aetiologies behind the commonly encountered disorders, to reduce their frequency and improve welfare of chelonians.

BSAVA resources

Series of Client Information Leaflets on reptiles https://www.bsavalibrary.com/content/cilgroupreptiles

BSAVA Manual of Reptiles https://www.bsavalibrary.com/content/book/10.22233/9781905319794

Reference

1Hornby JM, Hedley J, Brodbelt DC, Church DB & O’Neill DG (2025) Demography, commonly recorded disorders and mortality in chelonia under UK primary veterinary care: A VetCompass study. PLOS One. https://doi.org/10.1371/journal.pone.0321038

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