question: Do animals have any sense of their own mortality (other than when they are actually in the process of dying)?
comment: This entirely depends on the animal. Some animals at least have a survival instinct, but I think your question is more about having the intellectual capacity to understand what death is. Off the top of my head I know elephants will take the time to mourn one of their own who has died. There was a video I recently saw where a matriarch of this elephant herd died and the rest of the herd all came to “pay respects.”
passages: Despite appearances, the animal remains conscious throughout tonic immobility. Evidence for this includes the occasional responsive movement, scanning of the environment and animals in TI often taking advantage of escape opportunities.
  
  Section::::Tonic immobility.:In sharks.
   Section::::Marc Bekoff's Recent Research on Animal Grief.
  
  Marc Bekoff is a professor of ecology and evolutionary biology at the University of Colorado-Boulder. He has spent his life studying animals and their emotions, finding that animals grieve quite frequently. Such examples of grieving animals are:
  
  BULLET::::- Bekoff found that sea lion mothers squeal eerily when they watch their babies be eaten by killer whales.
  
  BULLET::::- Even after their calves have died, dolphin mothers have been seen to save them and grieve when they confirm the death.
   Tonic immobility has been used to show that hens in cages are more fearful than those in pens, hens on the top tier of tiered battery cages are more fearful than those on the lower levels, hens carried by hand are more fearful than hens carried on a mechanical conveyor, and hens undergoing longer transportation times are more fearful than those undergoing transport of a shorter duration.
  
  Tonic immobility as a scientific tool has also been used with mice, gerbils, guinea pigs, rats, rabbits and pigs.
  
  Section::::Thanatosis.
   BULLET::::- Chimpanzee orphans can die while in the state of grieving. Jane Goodall (1990) followed Flint, a chimpanzee, for a few days after the death of Flint's friend Flo. She noted that Flint "walked along one of the branches, then stopped and stood motionless, staring down at an empty nest". Flint had been lethargic, even refusing food. Per Goodall, Flint was "hollow-eyed, gaunt and utterly depressed".
  
  BULLET::::- Magpies have been seen to mourn over their dead.
   A case is shown with one named Amos. The day before he died he spent the day in his nest and did not move until a female chimpanzee Daisy went up to him (Safina, 2015). When Amos died, one of the chimpanzees who was more sociable than the rest as well as a “higher rank” than the rest did not want to be with the group for weeks. As shown here it also depends on who passed away on how long an animal can grieve. Though through the time spent mourning many signs can appear of an animals grief and agony of the loss of their companion.
   BULLET::::- Elephants have been "observed to stand guard over a stillborn baby for days with their head and ears hanging down". Orphan elephants, who have watched their mothers be killed, have been shown to wake up screaming.
  
  BULLET::::- A wolf "sniffed [her dead companion], then sat back and gave the most soulful and heart-wrenching howl I've ever heard!"; After a pack member died, the wolves let their tails and heads hang low while walking slowly.
   Elephant researcher Martin Meredith recalls in his book an occurrence of a typical elephant death ritual as witnessed by Anthony Hall-Martin, a South African biologist who had studied elephants in Addo, South Africa, for over eight years. The entire family of a dead matriarch, including her young calf, were all gently touching her body with their trunks, trying to lift her. The elephant herd were all rumbling loudly. The calf was observed to be weeping and made sounds that sounded like a scream, but then the entire herd fell silent. They then began to throw leaves and dirt over the body and broke off tree branches to cover her. They spent the next two days quietly standing over her body. They sometimes left to get water or food, but they would always return.
   Though Bekoff is the face of recent research on animal grief, other scientists are starting to look more into it. Some studies have looked at depression in animals, with Paul Willner finding that there are eighteen animal models of depression. Peter J. Fashing & Nga Nguyen (2012) found that a group of chimpanzees groomed and caressed a grieving, older chimpanzee. They also found that "the dying female [elephant] was approached by the matriarch of another group who repeatedly attempted to bring her to her feet using her tusks". Even otters grieve, where members of a group caught fish for months and brought them to the matriarch who had failing vision and poor mobility.
   One of the questions that can be asked aside from do animals grieve is how long do they grieve for or if these animals show signs of mourning. Anthropologist Barbra J King mentions how animals might sleep less or change their ways in their daily life styles. These animals might also end up staying close to their companion's corpse for a long time as well (Safina, 2015). Something we know is that emotions in a human can change, one day they can be sad and the other happy. Actions are taken days after one of our loved ones die, such as time of school, work or any social interaction (Safina, 2015). It is actually the same for animals. An example that can be shown is in chimpanzees.
   Another example mentioned is the dog Hachiko from Tokyo. In this case the dog was not grieving due to the death of an animal, but of the loss of its owner. It is known that this dog went to the station where his owner would come home to every day for around ten years.
  
  Section::::Other Research on Animal Grief.
   Many animals that appear to be depressed or grieving begin to exhibit self-destructive behavior that sometimes ends in death, but this is not considered suicide, as the achieving of death was not necessarily the purpose or objective of the behavior. In 1845, the "Illustrated London News" reported that a Newfoundland dog had been acting less lively over a period of days before being seen "to throw himself in the water and endeavor to sink by preserving perfect stillness of the legs and feet". Every time he was rescued he attempted to do this again before he finally held his head underwater until death. 
   Section::::Implications of Research.
   Animal loss
  
  The death of a pet or an animal to which one has become emotionally bonded can be an intense loss, comparable with the death of a human loved one, or even greater depending on the individual. The death can be felt more intensely when the owner has made a decision to end the pet's life through euthanasia. While there is strong evidence that animals can feel such loss for other animals, this article focuses on human feelings, when an animal is lost, dies or otherwise is departed.
  
  Section::::Effect of animal loss on humans.
   Death feigning behaviour can be deliberately induced by humans, a prominent example being the "hypnosis" of chickens or pigeons. For example, if a pigeon is grasped firmly, quickly inverted and held briefly on its back on a table, it often remains immobile for a minute or two. According to Gilman et al. the investigation of 'animal hypnosis' dates back to the year 1646 in a report by Kircher. It has been shown that the intensity and duration of death feigning is related to the intensity of fear prior to the feigning state being induced. This has been used to show that hens in cages are more fearful than those in pens, hens on the top tier of battery cages are more fearful than those on the lower levels, hens carried by hand are more fearful than hens carried on a mechanical conveyor, and hens undergoing longer transportation times are more fearful than those undergoing transport of a shorter duration.
   A well-researched form of deception is feigning death, often referred to by non-specialists as "playing dead" or "playing possum", although specialists use the terms "tonic immobility" or "thanatosis". A wide range of animals, e.g. lizards, birds, rodents, and sharks, behave as if dead as an anti-predator adaptation, as predators usually take only live prey.
   BULLET::::- After a fellow goose died, Konrad Lorenz noted that other geese had their "eyes sink deep into their sockets, and the individual ha[d] an overall drooping experience, literally letting the head hang".
  
  Section::::How Long Do Animals Feel Grief?
   A question that is asked is if animals have any emotions? Marc Bekoff defines emotion as something that helps behavioral control and management (Bekoff, 2000). It is known that humans have emotions and that it is something fundamental and important in our lives, however it is hard to say if that is true for animals or just some. There are different ways you can tell the emotion of animal: how they’re acting or how they’re looking at someone or something.
  
  Section::::Animal Emotions.:Primary Emotions and Secondary Emotions.
   Occurrences of elephants behaving this way around human beings are common throughout Africa. On many occasions, they have buried dead or sleeping humans or aided them when they were hurt.
   Another example of an alleged case of animal suicide is the case of the dolphin which most often portrayed Flipper on the 1960s television show "Flipper". According to trainer Ric O'Barry in the film "The Cove," Kathy, the dolphin, suffocated herself before him. The veracity or accuracy of this case hasn't been established in rigorous, scientific or objective terms. Suicidal behavior has been observed more in female animals than male and in more vertebrates than invertebrates.
   To induce tonic immobility, the animal is gently restrained on its side or back for a period of time, e.g. 15 seconds. This is done either on a firm, flat surface or sometimes in a purpose-built ‘V’- or ‘U’-shaped restraining cradle. In rodents, the response is sometimes induced by additionally pinching or attaching a clamp to the skin at the nape of the neck. Scientists record behaviours such as the number of inductions (15-second restraining periods) required for the animal to remain still, the latency to the first major movements (often cycling motions of the legs), latency to first head or eye movements and the duration of immobility, sometimes called the ‘righting time’.
   There are also some who reject the argument entirely, arguing that although suffering animals feel anguish, a suffering plant also struggles to stay alive (albeit in a less visible way). In fact, no living organism 'wants' to die for another organism's sustenance. In an article written for "The New York Times", Carol Kaesuk Yoon argues that:
  
  Section::::Scientific approaches.:Cognitive bias and emotion.
   Death feigning may also play a role in reproduction, for example, in the nursery web spider, the male sometimes feigns death to avoid getting eaten by females during mating. In some cases, death feigning is used by a predator. For example, the predatory cichlid "Haplochromis livingstoni" lies on its side on the bottom sediments until approached by scavengers attracted to what appears to be a dead fish, whereupon "H. livingstoni" abandons the pretence, rights itself and attacks the scavenger.
   In 1879, Arthur E. Brown studied how a male chimpanzee reacted after the death of his female counterpart. He saw the male chimpanzee display grief and "a cry which the keeper of the animals assures [Brown] he had never heard before"). Continuing to the next day, the chimpanzee sulked and barely moved. Brown deciphered that the male chimpanzee was depressed after the female chimpanzee died. However, Brown concluded that any permanent grief is only found in man, as the chimpanzee seemed fine after a couple of days.
   Scientists debate the extent to which elephants feel emotion. They appear to show interest in the bones of their own kind, regardless of whether they are related. As with chimps and dolphins, a dying or dead elephant may elicit attention and aid from others, including those from other groups. This has been interpreted as expressing "concern"; however, others would dispute such an interpretation as being anthropomorphic; the "Oxford Companion to Animal Behaviour" (1987) advised that "one is well advised to study the behaviour rather than attempting to get at any underlying emotion".
  
  Section::::Conservation.
  
  Section::::Conservation.:Status.
   Secondary emotions are part of an experience. These emotions are taking part in the central cortex of the brain because of the requirement of different and higher brain centers. With secondary emotions it allows one (in this case the animals that do feel grief) to create the connection between feelings and actions.
  
  Section::::Early Research on Animal Grief.
  