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established for the first few hours after death, but there is only minimal data on distinct species of animals and human data cannot be simply extrapolated to individual animal species. Further, scavenger activity after death and mummification can be misinterpreted as stages of decomposition. Thus, determination of post-mortem interval based solely on the characteristics mentioned above is 55 scientifically not well established and no practical field application is available. Caution is needed when interpreting the findings! Nevertheless, careful assessment and documentation of the post-mortem changes seen in a carcass must be performed by the pathologist. It has recently been found that the intraocular pressure may be a good indicator for short (< 12 hours) post-mortem intervals and this method may hold future potential if validated in various species of animals. Other methods, e.g. variations in various body fluids characteristics, have not proven successfully in humans, let alone animal species. Carcasses in wildlife forensic cases are often found at later stages of the post-mortem period, rendering the above-mentioned methods (lividity, cooling, rigidity etc.) useless. In such cases, entomological investigations of the insects and different stages of larvae that colonize a carcass after death may provide fruitful information on the minimum time (i.e. larvae need a certain time to develop even under “best” conditions) elapsed since death. For more information on this technique, the reader may refer to the chapter on entomological investigations in this book. 6.1.4 Special findings in pathological investigations 6.1.4.1 Pathological findings due to Electrocutions Electrocution is almost exclusively found in birds shortcutting the current while perching on and, especially, while lifting off from electrical wires. Electrical fences used to fence off a pasture, e.g., will not inflict any damage to ground dwelling animals due to their low intensity of current. Electrical current usually travels the shortest route through the body from the contact point to the point of exit. In the body, the current flows along the least resistant tissues, especially nerves, blood vessels and wet tissues. Death usually occurs due to acute heart fibrillation and cardiopulmonary arrest or brain damage. Pathological findings may range from extreme thermal burns to very subtle, almost nondetectable local marks, especially when the tips of feathers were the sole contact points. 56 Traumatic amputation of wings, legs or digits may occur through severe muscular contractions due to the current agitating the nervous system. During necropsy, carefully inspect the wings and wrists for charred feathers. However, these may be difficult to distinguish from dirt and the use of a dissecting microscope is recommended. Further, charred feathers and skin may be detected by using an alternate light source at 530 to 570nm under a red filter. Inspect the feet for any discolorations. Further, check the complete skin of the carcass for entrance and exit holes of the current. These holes may exhibit only subtle charring. Internal damage may comprise severe thermal injuries when the current entered the body for a prolonged period (e.g. when the bird was entangled after death). Muscles may exhibit a cooked appearance and discoloration and ruptures of viscera may occur. However, in many cases, internal damage is almost non-existent when the electrocution was very quick. Histopathology may show coagulation necrosis and intraepidermal separation in the skin. Figure 19: Extensively charred feathers in an electrocution victim (Source and © Ildiko Szabo/Beaty Biodiversity Museum) 57 6.1.4.2 Pathological findings due to collisions with vehicles or other man-made structures (windmills, power lines etc.) Remember that an animal may not die instantly at the site of a vehicle collisions and hence is not necessarily found on or close to a road. Thus, finding an animal in a field or forest does not rule out a vehicle collision! Many kinds of mammals and birds may collide with vehicles or trains. In small species, a frontal collision will result in multiple and severe, mostly blunt force, traumatic lesions, including bone-fractures, luxations, laceration and ruptures of inner organs and tissues. Multiple bleeding in various tissues will be prominent. Injuries to body areas that are remote from the direct impact area may be present due to projection of the animal, coup-contrecoupe effects due to the rapid acceleration/deceleration process in collisions etc.. Multiple abrasions of the skin and dirt embedded in the fur are often found in collision-victims. Large collision-victims with massive muscles and/or thick layers of fat like bears may show only subtle pathological changes like bleedings in the hide and musculature when hit not frontally but in a peripheral region. External examination may reveal no obvious wounds, but check the exterior for vehicle paint chips. Nevertheless, because of the forces involved in collisions, death can occur due to rupture of inner organs and subsequent internal bleeding. Flying birds may also be killed by larger or fast travelling vehicles by the downdraft created by them, i.e. no direct hit. In windmill victims (birds), lacerations of the lungs may be a prominent feature. 6.1.4.3 Pathological findings in snaring/trapping victims Remember that the traps and snares removed from a carcass are forensic evidence and may yield fingerprints and DNA of the perpetrator. Careful handling with gloves and appropriate evidence management should thus be ensured. As a general rule, animals found dead in traps and snares should always be radiographed since sometimes the victims were entangled alive and killed by shooting. The intensity of injuries due to illegal snaring/trapping largely depends on the species of animals involved and the devices used. 58 In smaller animals, jaw traps will have devastating effects with complete crushing and tear-off of feet, neck, wings and other body acra. In large animals, roundish, superficial to deep and sharp to blunt force traumata around the limbs are very common, as well as fractures of the extremities or the parts of the body where the jaws of the