There are many approaches to asking questions about animal behaviour. Firstly we should have an idea in mind defining what behaviour is.
Behaviour can be defined as;
All observable processes an animal responds to in the external world or in the internal state of its body & Any action that can be observed and described, and must be observable and describable.
The latter is a relatively broad definition, ranging from slight muscle twitches to sophisticated displays.
Methods in asking questions about behaviour
There is an inherent consistency to many behaviour patterns displayed by animals. Repeatable measures allow for reliable repeatable observations of individuals, of a species. This is because members of a species share behaviours that are general and recurring. These patterns are identifiable activities, recognisable and distinguishable from other identifiable patterns preformed by the species.
Functions of behaviours
Animals appear to do things in order to achieve something, i.e. carry out particular behavioural patterns or sequences of behaviours that have a functional response, and this is reflected in how we describe behaviour:
Searching for food
Hiding from predators
Attracting a mate
Displaying to a competitor
The means to an end
We can interpret apparent purposefulness as indicating some kind of internal representation of what has to be achieved, this could be a mental image; a squirrel sets out with an image of food in its head or a bird weaves twigs to its internal mental notion of a nest.
Goal directedness (Goal directed behaviour) describes this purposefulness based on internal representations. An example: The goal directed digging wasp digs burrows and stocks them with provisions for their larvae, when the burrow is finished and the larvae and rations are in place, the wasp moves on to dig another burrow. But how does the wasp know when a burrow is finished? Perhaps she works to an internal representation of what a burrow should be, expressing goal directed behaviour or she may simple be digging down for X number of minutes and laterally for Y number of minutes.
A manipulative experiment was carried out, artificially extending and filling in burrows digging wasps were working on.
The experiment showed; wasps would extend burrows which were filled in, and fill in burrows which were artificially extended. This indicates the digging wasp exhibits goal directed behaviour and have an internal representation, some criterion for deciding when a burrow is finished.
Goal achieving behaviour is where an animal has no internal representation of its goal. The goal is only recognised when it has been encountered, woodlice express goal achieving behaviour.
Woodlice are found in dark moist environments, but do not set out to find them. If an individual finds itself in a bright and dry environment, it starts walking. The louse moving somewhat randomly does not know where it’s going, just where it prefers not to be. The brighter and drier the conditions of this unsavoury environment the quicker the woodlouse will move. When the louse finds itself in a sufficiently dark and moist environment it will recognise this as where it wants to be. The goal is recognised once it is encountered.
Locomotory responses are taxes and kineses: Taxes are orientated responses – Phototaxis is a direct response to light. Kineses are non-orientated responses – Hydrokinesis is a somewhat random response to moisture.
There are different levels at which you can study animal behaviour:
Tinbergen is one of the founders of the modern study of animal behaviour for which he won a noble prize in 1973. Tinbergen split the study into four questions:
1) Mechanism: how is a particular behaviour achieved? How does an animal use its sensory and motor abilities to achieve/modify its behaviour? It’s the mechanism within the animal of the body itself.
2) Development: How does behaviour develop? How does an animal’s behaviour change during growth in response to experience (a = gene, b = environment: it could be a or b, or an interaction between a + b) e.g. pollutants in the environment can change an animal’s behaviour.
- Mechanism and Development approaches are proximate approaches looking at proximate measures in the animal to discover how behaviour is achieved and developed.
3) Function: What is the behaviour for? How does it promote survival and reproduction? How is it selected for over time?
4) Evolution: Where has the behaviour come from? We can compare the behaviour of closely and distantly related species, what does this tell us about the origins of the behaviour? In birds, simple pecking can evolve into complex displays, for example.
- Function and Evolution are ultimate approaches relating to the survival, reproduction and evolution of the animal.
There are several techniques used to answer Tinbergen’s questions:
1) Experiments: Manipulating variables of interest and controlling or remove confounding factors. Manipulative experiments are the most powerful way to distinguish between rival explanatory hypotheses.
2) Observations: Useful when manipulation is not possible or unethical. You can record unwanted variables and control in subsequent analysis’. Analysis must be driven by a priori predictions e.g. you should always test specific hypotheses.
3) Comparison: You can compare across different species and environments. Different selection pressures are expected to mould behaviour in predictable ways.
4) Theoretical modeling: Mathematical equations or computer programs can take essential elements of a system and can; make precise predictions, simulate outcomes and compare these to the real world.
The road to the modern study of animal behaviour.
Ethology led to behavioural ecology using hypotheses driven investigation, it is the biological study of behaviour. Ethology is an all encompassing European approach to how and why animals achieve things, covering the four different aspects. A wide range of species were studied in their natural context. It gave detailed descriptions of behaviour but declined due to lack of experimental support.
Comparative psychology is the American approach looking for general laws of behaviour applicable to all species, focusing on mechanisms and development. Contrasted with Ethology, by studying adaptive specialisation, with an emphasis on fixed behaviour patterns.
Behavioural ecology is the dominant field in the study of animal behaviour. It is a mixture of Ethology, Ecology and Evolutionary Biology focusing on questions of evolution and function. It’s a very successful predictive science e.g. Evolutionary Stable Strategies (ESSs), where adaptive decision making is often frequency dependent. Criticism include: Has a reduced focus on mechanism and development and it views many aspect if an organism as a perfect adaptation to something.
Evolutionary psychology is a relatively new discipline and primarily focuses on human cognition. In the past psychologists talented to focus on mechanisms of learning but ignored it adaptive value, how it evolved over time but have since recognised the importance of natural selection.
Is the study of animal behaviour what you thought it would be?
- Barnard, C (2004). Animal Behaviour: Mechanism, Development, Function and Evolution. Pearson Education Limited, Essex.
- Salonen, A. & Peuhkuri, N (2006). The effect of captive breeding on aggressive behaviour of European grayling, Thymallus thymallus, in different contexts. Animal Behaviour 72: 819-825