NATIVE RODENTS
10.1 Capture and physical restraint
Various options are available for capturing free-ranging rodents or those in large enclosures (Table 9.4).
Rodents will try to avoid capture and often bite.
Improper handling can result in injury to the animal and/or handler. Grasping the tail of many Australian rodents may result in degloving injury. Handling time should be kept short to reduce stress or risk of injury to the animal (Breed and Eden 2008). Smaller species can be grasped firmly by the scruff of the neck while supporting the body with the other fingers of the same hand. Larger species can be restrained by positioning the head between the index and middle fingers of one hand, while the other hand supports the hindquarters. Gloves can be used when handling larger species. Rodents can be restrained through a cloth bag and examined by turning the bag inside out while still maintaining a hold on the animal through the bag. Clear plastic bags can be used to restrain, measure and sex rodents with minimal need for direct handling (Breed and Eden 2008; NHMRC 2014).10.2 Chemical restraint
Chemical restraint is preferable for prolonged or more invasive procedures. A range of injectable tranquilisers, sedatives and anaesthetic agents have been used in nonnative pet rodent species, but these are not routinely used in Australian native rodents. Butorphanol has been used as a pre-anaesthetic agent in rodents (see Appendix 3).
Pre-anaesthetic fasting requirements are provided in Table 9.1. Inhalation anaesthesia using isoflurane or sevo- flurane in oxygen is the preferred method. Induction can be achieved using a face mask with the animal either physically restrained or in a cloth bag or an induction chamber. Anaesthesia is usually maintained via a face mask because endotracheal intubation is difficult. Blind intubation is possible, although difficult.
A simple bubble-through vaporiser has been used for very brief field anaesthesia of rodents (Fig. 9.16, Table 9.7).Table 9.4. Capture methods for rodents (NHMRC 2014)
| Method | Comments |
| Pitfall traps | Useful in arid and open habitats. Animals removed from traps either with a bare hand and grasping the scruff of the neck and transfer into a bag or by covering the hand with a cloth bag, grasping the scruff of the neck through the bag, removing the animal from the trap while inverting the bag over it |
| Elliot traps (baited) | Useful for forest-dwelling or rodents held in managed care. Trap can be tipped to slide the animal into the bag |
| Cage traps (baited) | For larger species, such as the water rats; for arboreal species, baited smaller cage traps set in trees. Animals removed from traps by placing a calico bag over one end of the trap and encouraging animal to move into the bag |
11.