Carcass class

Updated on 04 June 2015

Carcasses are categorised for MIKE by four broad classes. Correctly determining the actual time of death (i.e. three days, six weeks, etc) of a carcass is extremely difficult, as many factors change how fast a carcass decomposes – as a result, we use these broad categories.

Carcass classes were initially developed for aerial survey, where quick determination had to be made as to a carcass’ stage of decay. Working with a carcass on the ground, where you have more time, affords more time to see more detail and perhaps make a better determination – but it can also be confusing as characteristics of each stage may be mixed.
 

Here we present an overview of the carcass stages, followed by detailed notes on each category. See the checklist for on-site determination. Each category gives the name (fresh, recent, etc), key points in bold, followed by detailed characteristics that may be found.

Note:

  • 2013-04-12: the key points and characteristics are a broad guide and are under review; individual sites may use minor variations on these guidelines. Please email us any comments that you might have.
  • Carcasses under dense, wet cover (e.g. thick forests) may decompose differently and notes are indicated in each carcass class.

The categories are:

  1. Fresh: carcass still has flesh beneath the skin, giving a rounded appearance.  Vultures are probably present, and a pool of body fluids is still moist on the ground.
  2. Recent: presence of an open, discoloured rot patch around the body where plants have been killed.  Skin is usually present and bones are usually not very scattered (although if there are a lot of predators in the area they may be).
  3. Old: no rot patch – often, plants are now growing again.  Carcass is now a skeleton, with clean white bones and often no skin.  In arid areas some skin may be present still.
  4. Very old: the bones are cracking and turning grey.  Skeletons are difficult to see from the air.

Fresh

Key: the carcass is WET, has a rounded appearance.

The characteristics may include:

 

  • A complete body before rigor mortis, without any signs of scavengers, maggot infestation or any human interference (normally only found when working with authorities on problem animal control).
  • Round swollen body with decomposition fluids flowing from natural and predator openings
  • Living maggots. The age, body size and distribution of maggots my indicate the duration of animal death.
  • Wet intestines within the body and extracted within a short distance from abdomen
  • Carcass area covered by decomposition fliuds with evident signs of dying plants from effects of the fluids
  • Skin wet
  • A  strong punget-acrid smell from decomposing soft tissues
  • Scavengers active on the carcass
  • Fresh and dry droppings of scavengers evident, including vultures and carnivorous mammals.

Forest habitats:

  • Ants play a much larger role in decomposition of carcasses.

EC1 Sony Download 30 Mar 2008 046 SM

Recent

Key: a rot patch around the body, carcass is dry and no meat is left.
  • Body not rounded or swollen, shrunken
  • No strong smell from decomposing tissues
  • A proportion of bones still attached to skin but easily detachable
  • Several groups of bones joint by tissues, pieces of tissue still present on skin
  • Rot patch also after fluids kill all vegetation on the death spot
  • Death spot dry (no wet fluids) and stomach contents present.
  • No fresh or recent signs of vultures
  • Dry, desiccated skin.
  • Evident feeding signs of mammalian scavengers e.g. gnawing of bones and old tissue

 

Forest habitats:

  • Carcasses do not dry out quickly, but no meat is left.
  • The presence of the stomach contents still indicates ‘recent’, but the skin may disappear quickly.
  

 

 

EC2 IMG_0009

Late-stage ‘Recent’ – rot patch is still visible

Old

Key: white bones, no rot patch.

  • Bones white and ‘glowing’ in sunlight
  • Bones scattered away from original death spot
  • Very scanty tissue on bones
  • No rot patch. Original death spot overgrown by vegetation
  • Signs of mammalian scavenger action on the bones
  • Few cracks appearing on bone surfaces
  • No signs of stomach contents or remains of intestines, and no skin remains

Forest habitats:

  • Bones may never be white, instead may have green discolouration from algae (see image opposite).
  • Depending on the habitat, there may be little movement of bones from the original death spot due to mammalian scavengers, and if there are no hyaenas most of the bones will be intact.
EC3 regrow

Bones are not completely white, but the rot patch has regrown.

 

Bones in forest environment: green and discoloured, but scattered and no tissue remains.
Bones in forest environment: green and discoloured, but scattered and no tissue remains.

Very old

Key: gray bones, very scattered.

  • Very few bones of the animal
  • Grey in colour
  • Cracked and easy to crumble
  • Bones usually scattered further away from original point of death.
  • Death spot completely disappeared
EC4

Bones are scattered widely, hard to see.

Bones are cracked, gray and crumbling.

Bones are cracked, gray and crumbling.

 

Difficulties

  • All stages: Bone scattering is affected by frequency of hyena and other elephants
  • Old vs. very old: May be difficult to distinguish white from gray bones; the onset of coloration is dependent on environmental and climatic factors
  • Recent vs. old: Rot patch development depends on size of animal, the physical conditions of the death spot (rocky conditions, river bed, swamp etc.), and human interference. The lack of any tissue on the bones should indicate ‘old’ where there are problems in determining the status of a rot patch.

Relevant References