Using Data-Compressors for Classification Hunting Behavioral Sequences in Rodents as “Ethological Texts”

Abstract

One of the main problems in comparative studying animal behavior is searching for an adequate mathematical method for evaluating the similarities and differences between behavioral patterns. This study aims to propose a new tool to evaluate ethological differences between species. We developed the new compression-based method for the homogeneity testing and classification to investigate hunting behavior of small mammals. A distinction of this approach is that it belongs to the framework of mathematical statistics and allows one to compare the structural characteristics of any texts in pairwise comparisons. To validate a new method, we compared the hunting behaviors of different species of small mammals as ethological “texts.” To do this, we coded behavioral elements with different letters. We then tested the hypothesis whether the behavioral sequences of different species as “texts” are generated either by a single source or by different ones. Based on association coefficients obtained from pairwise comparisons, we built a new classification of types of hunting behaviors, which brought a unique insight into how particular elements of hunting behavior in rodents changed and evolved. We suggest the compression-based method for homogeneity testing as a relevant tool for behavioral and evolutionary analysis.

Information Theory Opens New Dimensions in Experimental Studies of Animal Behaviour and Communication

“…It is worth noting that quantitative estimation of the complexity of sequences in natural texts is of interest in its own right [ 17 ]. A huge body of literature analyses symbolic sequences by means of Kolmogorov complexity, including diagnostic of the authorship of literary and musical texts (reviews in [ 17 , 22 ]). The measure is based on Kolmogorov complexity when evaluating the complexities of texts in different languages.…”

“…This method belongs to the framework of mathematical statistics and allows pairwise comparisons. In the case of ethogram comparison, this approach allows quantifying the degree of structural similarities and differences between behavioural sequences as ethological “texts.” Levenets et al [ 22 ] developed this method to evaluate structural differences between hunting behaviours in nine species of small mammals with various ecological traits and different diets. The authors recorded hunting behaviour towards an insect in individual members of eight rodent species and the insectivorous shrew as a “standard predator.” The authors tested the hypothesis of whether the behavioural sequences of different species as “texts” are generated either by a single source or by different ones.…”

“…The authors applied the open-source data compressor 7-zip v. 18.05 (64-bit), which uses the method of data compression called Bzip2, (compressed file format bz2). Preliminary, the researchers compared three data compression algorithms, namely, LZMA, Deflate, and BZip2, and chose the one that compressed better (see details in [ 22 ]). Based on the association coefficients obtained from pairwise comparisons, the researchers built a new classification of types of hunting behaviours, which brought a unique insight into how hunting behaviour in rodents possibly changed and evolved.…”

“…The first part of this review concentrates on applying information theory to the comparative analysis of stereotyped behaviours that enable animals to accomplish particular goals, such as chasing prey, avoiding a predator, or defending territories. The method of analysing ethological texts based on ideas of Kolmogorov complexity can serve many goals, from distinguishing between stereotyped and flexible parts of behaviours to understanding the evolutionary roots of complex stereotypes within animal lineages, such as rodents’ families [ 17 , 20 , 21 , 22 ]. The second part considers studying animal intelligent communication using an experimental approach based on Shannon entropy and Kolmogorov complexity [ 18 , 19 , 23 ].…”

Comparative analysis of optional hunting behavior in Cricetinae hamsters using the data compression approach

“…Among all these Cricetinae species, the behavioral patterns of insect hunting have been studied only in four hamster species, from the simplest variant in P. sungorus and P. campbelli , to the more specialized in A. eversmanni and A. curtatus [ 26 ]: in both Allocricetulus species, hunting behavior was obligatorily displayed in all individuals, combined with the ability to initiate an attack by seizing with the paws, which is a sign of specialized hunting behavior [ 16 ]. The mathematical analysis revealed the quantitative behavioral similarities between the latter two species and the generalized predator Norway rat ( Rattus norvegicus , Berkenhout, 1769), possibly caused by their particular abilities to manipulate forepaws when handling the prey [ 27 ].…”