Crocodilians

Darryl Heard

doi:10.22233/9781905319794.26

Crocodilians

British Small Animal Veterinary Association , 443 (2019); https://doi.org/10.22233/9781905319794.26

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Crocodilians

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Author: Darryl Heard
From: BSAVA Manual of Reptiles
Item: Chapter 26, pp 443 - 456
DOI: 10.22233/9781905319794.26
Copyright: © 2019 British Small Animal Veterinary Association
Publication Date: March 2019

Abstract

This chapter is an introduction to the medical management of crocodilians, covering anatomy, sexing, husbandry including handling and restraint, diagnostic approach, common conditions, supportive care, anaesthesia and analgesia, and common surgical procedures.

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Figures

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26.1

Crocodilians are not recommended as pets. Some species that may, however, be encountered by veterinary surgeons (veterinarians) include (a) the American alligator, (b) spectacled caiman and (c) the dwarf caiman. Some crocodilians can tolerate high densities as juveniles (e.g. alligators), but not as adults. © 2019 British Small Animal Veterinary Association

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26.1 Crocodilians are not recommended as pets. Some species that may, however, be encountered by veterinary surgeons (veterinarians) include (a) the American alligator, (b) spectacled caiman and (c) the dwarf caiman. Some crocodilians can tolerate high densities as juveniles (e.g. alligators), but not as adults.

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26.2

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26.2 Lateral radiograph of a dwarf caiman. Note the presence of the osteoderms (bony plates) within the scales.

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26.3

Crocodilian nares are located at the dorsorostral end of the maxilla. (a) The nares are usually tightly closed, except (b) during inhalation and exhalation. Crocodilians strenuously resist sampling from within the nares. © 2019 British Small Animal Veterinary Association

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26.3 Crocodilian nares are located at the dorsorostral end of the maxilla. (a) The nares are usually tightly closed, except (b) during inhalation and exhalation. Crocodilians strenuously resist sampling from within the nares.

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26.4

The openings to the ears are located immediately behind the eyes and covered by the auricular flap. The tympanic membrane can be visualized when this flap is raised, but awake animals will violently resist this movement. Leeches can occasionally be found under the flap. © 2019 British Small Animal Veterinary Association

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26.4 The openings to the ears are located immediately behind the eyes and covered by the auricular flap. The tympanic membrane can be visualized when this flap is raised, but awake animals will violently resist this movement. Leeches can occasionally be found under the flap.

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26.5

As in this estuarine or saltwater crocodile, the translucent third eyelid covers the eye during diving. It is well vascularized and contains inflammatory cells that may react to irritants and infectious agents. © 2019 British Small Animal Veterinary Association

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26.5 As in this estuarine or saltwater crocodile, the translucent third eyelid covers the eye during diving. It is well vascularized and contains inflammatory cells that may react to irritants and infectious agents.

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26.6

Cachexia in American alligators and other crocodilians is indicated by (a) prominent supratemporal fossae and (b) obvious pelvic bones and narrow neck, compared with (c–d) healthy animals. In severe cachexia the tail will turn laterally owing to loss of muscle mass. © 2019 British Small Animal Veterinary Association

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26.6 Cachexia in American alligators and other crocodilians is indicated by (a) prominent supratemporal fossae and (b) obvious pelvic bones and narrow neck, compared with (c–d) healthy animals. In severe cachexia the tail will turn laterally owing to loss of muscle mass.

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26.7

The oral cavity of an adult American alligator. Note the large sharp white teeth, the gular flap at the back of the throat, the large relatively immobile tongue and the wide powerful gape. © 2019 British Small Animal Veterinary Association

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26.7 The oral cavity of an adult American alligator. Note the large sharp white teeth, the gular flap at the back of the throat, the large relatively immobile tongue and the wide powerful gape.

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26.8

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26.8 The trachea of a Philippine crocodile, showing a normal lateral deviation of the trachea.

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26.9

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26.9 All crocodilians can be sexed by palpating the phallus on the ventral floor of the male cloaca.

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26.10

Cannibalism and intraspecific aggression is common in crocodilians. This is a major reason why usually animals of different sizes should not be housed together. © 2019 British Small Animal Veterinary Association

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26.10 Cannibalism and intraspecific aggression is common in crocodilians. This is a major reason why usually animals of different sizes should not be housed together.

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26.11

As in this yacare caiman, obesity is a common nutritional problem in captive crocodilians. Note the large jowls, abdominal distension and swollen limbs. Oedema from vasculitis, as in septicaemia, may resemble these clinical signs, but animals would also be depressed and weak. © 2019 British Small Animal Veterinary Association

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26.11 As in this yacare caiman, obesity is a common nutritional problem in captive crocodilians. Note the large jowls, abdominal distension and swollen limbs. Oedema from vasculitis, as in septicaemia, may resemble these clinical signs, but animals would also be depressed and weak.

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26.12

Medium to large crocodilians may be restrained on purpose-built boards with straps, to allow transport and minor diagnostic procedures. This caiman has its jaws taped shut with plumber’s tape, its eyes covered with bandage wrap and seat-belt straps for body restraint. This set-up is suitable for performing a computerized axial tomography (CAT) scan in small- to medium-sized awake animals. © 2019 British Small Animal Veterinary Association

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26.12 Medium to large crocodilians may be restrained on purpose-built boards with straps, to allow transport and minor diagnostic procedures. This caiman has its jaws taped shut with plumber’s tape, its eyes covered with bandage wrap and seat-belt straps for body restraint. This set-up is suitable for performing a computerized axial tomography (CAT) scan in small- to medium-sized awake animals.

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26.13

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26.13 Sample history form and questions.

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26.15

Blood collection from the supravertebral sinus. After disinfecting the skin, (a) the deepest depression (C1–C2) behind the skull is palpated, (b) the needle is inserted perpendicularly in the midline and, with a slight suction on the syringe, advanced until blood is aspirated. © 2019 British Small Animal Veterinary Association

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26.15 Blood collection from the supravertebral sinus. After disinfecting the skin, (a) the deepest depression (C1–C2) behind the skull is palpated, (b) the needle is inserted perpendicularly in the midline and, with a slight suction on the syringe, advanced until blood is aspirated.

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26.16

(a) The ventral coccygeal vessels (artery and veins) are located immediately below the vertebral body (V) as shown in this cross-section of the tail of an American alligator. They can be accessed from the ventral midline between the ventral spinous processes (VP) or (a–b) from the ventrolateral surface of the tail (arrowed). (c) The ventral coccygeal vessels can be catheterized for fluid administration. © 2019 British Small Animal Veterinary Association

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26.16 (a) The ventral coccygeal vessels (artery and veins) are located immediately below the vertebral body (V) as shown in this cross-section of the tail of an American alligator. They can be accessed from the ventral midline between the ventral spinous processes (VP) or (a–b) from the ventrolateral surface of the tail (arrowed). (c) The ventral coccygeal vessels can be catheterized for fluid administration.

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26.17

A computerized axial tomography (CAT scan) cross-sectional image of the lung of an American alligator. This is the recommended diagnostic modality for identifying respiratory disease (including fungal pneumonia) in crocodilians. © 2019 British Small Animal Veterinary Association

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26.17 A computerized axial tomography (CAT scan) cross-sectional image of the lung of an American alligator. This is the recommended diagnostic modality for identifying respiratory disease (including fungal pneumonia) in crocodilians.

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26.19

A juvenile American alligator with a surgically placed oesophageal tube for repetitive enteral feeding and drug administration. This route is useful in animals that are anorexic, but otherwise have normal gastrointestinal function. The tube can be extended down the back to facilitate safe administration. © 2019 British Small Animal Veterinary Association

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26.19 A juvenile American alligator with a surgically placed oesophageal tube for repetitive enteral feeding and drug administration. This route is useful in animals that are anorexic, but otherwise have normal gastrointestinal function. The tube can be extended down the back to facilitate safe administration.