What makes some species of milk snakes more attractive to humans than others?

Abstract

Animals are ancestrally important stimuli for humans who pay disproportional attention to animal objects and exhibit an outstanding ability to categorize animal species, especially those most relevant to them. Humans as well as other primates perceive snakes as ambivalent stimuli that elicit unspecific arousal and attention. We assessed human aesthetic preferences toward milk snakes, the traditional model for studies of Batesian mimicry. The genus is fairly uniform in size and shape, but includes a great variety of color forms; some possessing aposematic patterns while others being rather cryptic. This provides an opportunity to test which features are responsible for positive aesthetic evaluation of the species. We asked the respondents to rank 34 pictures of milk snakes according to perceived beauty. The sets (whole bodies, heads, and skin fragments) covered most of naturally occurring variation in milk snake appearance. While ranking the beauty, the respondents spontaneously classified the species according to two dimensions. In each set, one of the dimensions corresponds to perceived beauty. The respondents' ranking revealed several distinct clusters of species instead of a continuous gradient. The species clustered in a similar way irrespective of evaluated set. One dimension of the ranking associated with the relative representation of red color and the number of transversal stripes, the other corresponded to a low proportion of red and a high proportion of black color. When the whole body of the snake is evaluated, aposematic coloration contributes to its perceived beauty. In conclusion, humans showed a surprising ability to classify milk snake patterns; they repeatedly formed the same distinct groups of species, thus completing a process that resembles unsupervised categorization.

Cross-Cultural Agreement in Perception of Animal Beauty: Boid Snakes Viewed by People from Five Continents

“…The congruence among respondents within an individual culture was highly significant in all cases, and its level varied within expected limits (Marešová et al 2009b). The small cross-cultural differences that we revealed are dependent on the statistical method used and hard to quantify.…”

Does colour matter? The influence of animal warning coloration on human emotions and willingness to protect them

“…These results reflect generally higher support for birds and mammals among both conservationists (Clark & May, ) and the general public (Czech et al ., ) in all probability, as these may be privileged species because they are more positively socially constructed than reptiles, amphibians and invertebrates (Czech & Krausman, ). However, the present study demonstrates that the popularity of generally unpopular animals can be at least partly improved by presenting species with conspicuous, aposematic coloration, in which particular colours and their combinations that contribute to the perceived aesthetic of animals (Stokes, ; Knight, ; Marešová et al ., ; Barua et al ., ) remain to be studied. Animals were generally perceived as more dangerous/disgusting by females than by males.…”

“…Although experimental data are scarce, humans seem to perceive warning coloration as more highly conspicuous similarly than (confusing) natural predators (Bohlin et al ., ). Aposematically coloured species of milkweed snakes (Marešová, Landová & Frynta, ), brightly coloured butterflies (Barua et al ., ) and penguins with a warm colour (Stokes, ) are perceived as more beautiful than other species and the perceived aesthetic of animals is positively associated with a willingness to protect them (Knight, ). As far as we are aware, however, no study has experimentally investigated the role of animal coloration in the human willingness to protect animals.…”

Being Attractive Brings Advantages: The Case of Parrot Species in Captivity

“…The first one, which we further refer to as Ranking [37], [38], maximizes the informative content by covering the full ordination scale. It requires simultaneous presentation of all pictures to the respondent to allow relative comparisons, so it is hardly applicable to large sets.…”