4
Survival Strategies
‘It is not the most intellectual of the species that survives; it is not the strongest that survives; but the species that survives is the one that is able best to adapt and adjust to the changing environment in which it finds itself’
Leon Meggison
This piece of wisdom neatly encapsulates the Darwinian principle of survival of the fittest. Dinosaurs were extremely successful for 150 million years but failed to cope with a climatic catastrophe. The shark has managed very well without the need for change since the time of the dinosaurs because its environment hasn’t changed. Homo sapiens who arose less than one million years ago, has been more or less dominant for only the last few thousand and, in the last 200 years, largely through our invention of machines running on fossil fuels, has put our families and other animals at risk by threatening the habitat for all forms of life. We may be more intellectual but, according to the above definition, we are not proving to be a great success. Adaptation to the environment requires possession and development of the necessary machinery (e.g. limbs, claws, beak), senses (e.g. vision, hearing), skills (e.g. hunting, hiding) and mental ability (cognitive understanding and emotional intelligence). Different species have developed different abilities according to their different needs, which means that the same animal can be brilliant at some things, hopeless at others. The albatross appears to carry in its head a map of the southern hemisphere but fails to recognise its own chick if it falls out of the nest. It is meaningless to claim that one sentient species is more intelligent or more developed than another: each has developed the special senses and skills that it most needs. The corollary also applies. The wise saying, ‘we are all of us ignorant, we are just ignorant about different things’ applies not only to humans but right across the animal kingdom.
All sentient animals are born with a foundation of emotional and cognitive intelligence, an inherited operation manual and toolkit of physical and mental resources designed to promote survival and encourage wellbeing. Animals with sentient minds are able to build on this birthright, develop knowledge and emotional understanding of their physical and social environment, and hone special skills. All these properties of deep sentience enable animals to develop strategies designed to favour personal survival and reproductive success but, I repeat, they also carry the potential to cause suffering if, for any reason, they are thwarted in their attempts to carry them out.
Success, in Darwinian terms, is measured by the extent to which a species, or population within a species, is able to promote the survival and spread of its genes. Translating this into the day‐to‐day business of life, it is measured by the ability of individuals to promote their own survival, reproduce and further ensure the survival of their offspring. This principle, of course, applies to all living things. Here, I consider, by way of a few examples, how animals employ the inner circles of sentience to polish their strategies for survival, reproductive success and social wellbeing. These include the ability to acquire food through foraging or hunting, the ability to cope with complex environments through innate and acquired skills in spatial awareness and navigation, and the ability to protect one’s offspring until they are old enough to look after themselves.
Foraging
Charles Darwin is one of my heroes, not least because he considered all animals to be equally fascinating. In his later, housebound years, he wondered whether earthworms that pull fallen leaves down into the earth grab them at random or make decisions as to the most effective feeding strategy. He cut up paper into small triangles, observed the behaviour of the worms and discovered, to his great satisfaction, that they preferentially chose to grasp the paper at the point of an acute angle, thereby making it easier for them to get it underground. We may be confident this skill is hard‐wired, each earthworm does not work it out for him/herself (earthworms are hermaphrodites). It is a skill and it is one that calls for a decision, but one that strictly follows the instructions in the ancestral operation manual.
Involvement of the inner circles of sentience in the development of foraging strategies can be found throughout the animal kingdom. Here, I select a few choice examples
Honeybees: There are over 16 000 species of bees, most of which are solitary: individual females build a nest, lay down a source of food consisting mostly of pollen, lay a clutch of eggs, seal the entrance and leave the eggs to hatch into larvae that eat the pollen and emerge the following year as mature bees. The honeybee, exploited by us for its ability to gather and store food for us at minimal cost to us, is an exception. It is described as eusocial, which means that the whole population works for the success of the colony. The structure and social organisation of a colony of honeybees is well documented, hard wired, so not relevant to my theme. However, their foraging strategies are relevant because they reveal special skills some of which are similar to other animals of the air, some uniquely their own. The foraging strategy of the worker bees operates according to the rules that apply for any animal that needs to forage for food, namely, to maximise the harvest, especially energy‐rich food, relative to the energy cost of gathering that harvest. There are some variations in the way that bees go about gathering energy‐rich nectar but, as a general rule, a number of scouts go out in search of a good source. Each scout returns to the hive and conveys her findings to the other workers in the form of a ‘waggle dance’. This dance is performed on the vertical honeycombs inside the hide. It involves a series of figure‐of‐eight manoeuvres. She moves in a straight line waggling her abdomen from side to side, then loops back alternatively right then left to the starting point and repeats the sequence. The direction of her movement during the waggle sequence indicates the position of the food resource relative to the position of the sun (Figure 4.1). If the food source is directly in line with the sun, she dances vertically. When, as is usually the case, the food source is at an angle to the sun, she indicates the direction by adjusting her dance to the same angle from the vertical direction by dancing. The number of waggles in each sequence indicate the distance of the resource from the hive. The vigour with which she performs the waggles, and the number of repeats, give an indication of her estimate of the value of the resource (28).
Figure 4.1 The honeybee’s waggle dance
If all workers simply acted on information provided by a single scout, left the hive at once, got a bearing on the sun and followed the alignment to the sun indicated by the direction of the waggle sequence, they would all find the same food source at the distance indicated by the number of waggles. This is an impressive skill but not indicative of mental formulation. Moreover, it would not maximise foraging efficiency because that food source would quickly become exhausted. However, bee behaviour is not that robotic. The first variable is that the sun moves across the sky. Bees can take this into account because, like birds, they have a solar clock. A bee that sets out to forage in the afternoon will remember information as to direction relative to the sun conveyed in the morning and adjust for time of day. Moreover, the colony of individual bees in the colony do not respond en masse to a single piece of information. Several scouts will have been out and returned with information as to different food sources: their direction, distance and size of resource. Individual workers must then make decisions based on their estimate of the energy cost of travel to the resource relative to the likely reward measured by the size of the harvest. Different workers come to different conclusions, and this helps to ensure that the population achieves the most energy‐efficient harvest of the entire locality. Clearly, individual bees make individual strategic decisions as to the costs and benefits of the foraging options on offer. In terms of information processing, the complexity of this degree of understanding merits classification within circle four; mental formulation. We must, I think, assume that this degree of understanding is latent within the birthright of honey bees. The fact that different individuals within the colony come to different decisions as to the cost‐effectiveness of different foraging options is intriguing. It might suggest that they have the capacity to make judgements based on past experience. A more parsimonious explanation would be that different individuals are programmed to make different but consistent decisions based on different values given the proximity and size of the resource. This could be resolved by experiment.
Sheep: Given the opportunity to graze permanent pastures containing a variety of grasses, herbs and shrubs, sheep display an exquisite ability to select what is good for them. They avoid poisonous plants. This faculty, as with other animal species, is not simply based on how the food tastes when first they eat it. Shortly after eating a poisonous plant, they feel ill, remember this sense of malaise, associate it with the taste of the plant so learn to avoid it in future. They select nutritious plants, according to their specific needs for protein and energy, and there is some evidence that sheep with a high worm load will select plants with a high content of tannins having antiparasitic properties (41). They don’t need a degree in nutrition to achieve all this; all they need is to be extremely sensitive to feelings that matter and have the capacity to relate these to some property of the food; initially taste but on subsequent occasions presumably a combination of sight and smell. The section of their operation manual that covers diet selection will be contained in their birthright. However, each sheep will make its own choices from the available menu of foods that is most likely to meet its nutritional needs and least likely to do harm. I shall have more to say on feeding choices in sheep in Chapter 8.
Tool use: When chimpanzees were first observed to fashion tools by stripping leaves from sticks to extract insects from a termite mound, it raised great excitement because it was put forward as a demonstration of the capacity of a human‐like species to perform a behaviour previously assumed to be restricted to humans. Since then, once we started to look, we have found evidence that a wide range of animal species use tools when foraging for food that is not instantly accessible if, for example, it is hidden deep within a termite mound, or it has a protective coat, like nuts and shellfish, so needs to be got out of the tin.
Some birds and fish use stones to crack open nuts or break the shells of mussels. Wrasse, a marine fish, have been filmed opening scallops and clams held in their mouths by repeatedly swinging their heads to strike them against a nearby rock. Individuals probably learn this behaviour from observation of others, not necessarily their immediate family. The skills involved in tool use are far more advanced in corvid birds than primates. The most impressive performers in laboratory studies are the New Caledonian Crows. These birds display complex strategies for getting food from flasks, where it is seen but out of reach. These include fashioning a variety of complex tools, e.g. bending wire to make a hook, working out the correct sequence to solve an 8‐stage puzzle, and getting at a piece of meat attached to a cork floating in water by dropping pebbles into the flask until the water level rises to the top of the jar (84). This skill was first described in Aesop’s fable ‘The Crow and the Pitcher’, which strongly suggests that his fable was not just a work of imagination. Aesop had either seen it or obtained information from a reliable source, which means that crows have been doing this sort of thing for more than 2 000 years while under no pressure from researchers. There is abundant evidence that crows in the wild devise a wide range of strategies to get at inaccessible food, like the meat inside molluscs. These include relatively primitive approaches like hitting a mussel with a stone or dropping it from a height on to a hard surface. My favourite is the behaviour of crows at popular seaside resorts who gather mussels, carry them to the car park, then carefully place them at a spot where they know they will get run over by a car tyre.
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