Dasyurids and the numbat

6.1 Capture and physical restraint

The Family Dasyuridae contains 66 species, which range in size from 4 g up to 10 kg. Consequently, the methods used to capture and restrain them vary considerably.

Small free-ranging dasyurids can be captured using Elliot or pitfall traps. A variety of baits can be used in Elliot traps. Elliott traps must be covered with plastic bags to protect them from rain. In cooler areas, traps must contain bedding material to keep animals warm, as small dasyurids are prone to hypothermia. In hot weather, Elliott traps should be placed to avoid exposure to the sun. Pitfall trapping is the most common method for small dasyurids in arid habitats. Quolls and Tasmanian devils can be captured in PVC polypipe traps (‘poly trap’) (Fig. 9.8). The benefits of these traps are that they are fully enclosed, smooth-walled, insulated and provide protection from the weather; trapped individuals settle quickly; the smooth walls prevent biting or rubbing on the trap wall, minimising trauma; animals are easily

Fig. 9.8. Tasmanian devil (Sarcophilus harrisii) emerging from a PVC 'poly trap'. Photo: Save the Tasmanian Devil Program

removed by placing a sack over the entrance and tipping the animal into it; and the traps are easily cleaned and disinfected. Larger wire-mesh cage traps (covered to pro­vide protection from the weather) are used less often because trapped animals feel less secure and may bite at the wire.

Small dasyurids held in managed care can be caught in their nest box or with an Elliott trap. Larger dasyurids, such as quolls and Tasmanian devils, can be caught in a net or captured by the tail and lowered into a bag. The tail should be grasped about midway and animals can be held for short periods in this manner. Some quolls are agile enough to turn and potentially bite the handler. Smaller dasyurids should not be restrained by the tail, as deglov­ing injuries and tail fractures can occur. They can be gripped by the scruff of the neck or held firmly around the body without restricting respiration. Physical restraint of numbats is relatively simple and involves restraining the neck and shoulder area while supporting the hindlimbs (Vitali and Monaghan 2008). It is prefera­ble to place any dasyurid or numbat in a bag or sack soon after capture. They can be transported for short periods in bags, weighed, pouch checked, injected with anaes­thetic or other drugs or mask induced with gaseous anaesthesia (Holz 2008). Physical restraint is stressful and should only be used for minor procedures. Chemical restraint is recommended for most procedures.

6.2 Chemical restraint

Sedation for transport or any other purpose is generally not necessary, but if required diazepam IM provides good sedation (see Appendix 3).

Pre-anaesthetic fasting requirements are provided in Table 9.1. Inhalation anaesthesia using isoflurane or sevo- flurane in oxygen, with or without pre-medication, is preferred for dasyurids and numbats. Induction via a mask in combination with physical restraint with the animal in a bag with the head out or through the cloth is generally straightforward. An induction chamber can also be used. Numbats will often become apnoeic during induction (Vitali and Monaghan 2008). Injectable agents (see Appendix 3) can also be used in larger dasyurids if gaseous anaesthesia is not available.

Dasyurids have a wide gape and although the larynx is positioned relatively caudally, the glottis is easily visual­ised. Intubation is straightforward in the large- to medium-sized species. In smaller species, intubation is limited by the size of endotracheal tube available. Laryn- gospasm has been seen in some Tasmanian devils and can be prevented with the use of lignocaine spray (P Eden pers. comm.). Numbats are also easily intubated using an uncuffed 2-mm endotracheal tube.

7.