Dead reckoning in a small mammal: the evaluation of distance

Abstract

When hoarding food under infra-red light, golden hamsters Mesocricetus auratus W. return fairly directly from a feeding place to their nest site by evaluating and updating internal signals that they have generated during the previous outward journey to the feeding place. To test more specifically the animals' capacity to evaluate the linear components of the outward journey, the subjects were led from their (cone-shaped) nest to a feeding place along a detour which comprised either 2 (experiment 1) or 5 (experiment 2) segments; adjoining segments were at right angles to each other. In these conditions, the subjects remained significantly oriented towards the nest and therefore were capable of assessing translations as well as rotations during the outward journey. In experiment 3, the nest was removed after the hamsters had started the direct outward journey to the feeding place and the hamsters were rotated during the food uptake. The animals were no longer oriented towards the starting point of their journey, but nonetheless covered, along a fairly straight path, the correct homing distance, and then changed over to a circular search path. These results confirm that mammals can derive the linear components of an outward journey from self-generated signals and therefore are able to judge the homing distance without relying on cues from the environment. For a number of detour outward journeys, our data yield an unexpectedly good fit to Müller and Wehner's (1988) model of dead reckoning in ants. However, this is no longer the case when the outward journey contains an initial loop which brings the subject back to the starting point. These findings are discussed in terms of the biological significance and limitations of an approximate form of path integration.

Path integration in mammals

“…Hamsters (Séguinot et al, 1993), dogs , and humans (Loomis et al, 1993) are capable of estimating the beeline distance in which they walk through selfmotion cues. During active walking without vision, the assessment of path length depends less on inertial information than on nonvestibular motion cues, such as proprioceptive feed back and efference copies.…”

“…However, the general validity of these models may be questioned. For instance, the model failed to describe the homing trajectories of hamsters after a more convoluted outward trip that started with a loop around the point of departure (Séguinot et al, 1993;Maurer and Séguinot, 1995).…”

“…Without these cues, the animals continue their outward progression, in spite of the fact that the current state of their path integrator corresponds to the goal coordinates. During homing, when their path integrator indicates proximity to the nest, both species switch from a fairly linear homeward progression to circular movements in search of familiar cues near the nest entrance (Séguinot et al, 1993;Müller and Wehner, 1994).…”

Sensory information and associative cues used in food detection by wild vervet monkeys

“…Primates generally use a two-system model for navigation where spatial information can be represented in an egocentric (internal, relative to the body position and direction of motion) and/or an allocentric (external, relative to environmental cues) framework (Wehner and Srinivasan 1981;Etienne et al 1988Etienne et al , 1998Gallistel 1990;Wehner et al 1996;Dolins and Mitchell 2010;but see Wang and Spelke 2002). Use of egocentric representations alone may lead to the accumulation of errors in navigation (Séguinot et al 1993), and egocentric and allocentric localization appear to work in parallel in most situations to keep an animal oriented (Burgess 2006). The predominant use of one representation over the other may depend upon how much the animal is moving, the size and structure of the environment it is moving through, and prior experience within that environment (Burgess 2006).…”

Path integration in cockroach larvae,Blattella germanica (L.) (insect: Dictyoptera): Direction and distance estimation

“…Spiders estimate their position, relative to their shelter, using kinesthetic information gathered while moving and transmitted via exoskeleton proprioceptors located in their legs (Gomer & Claas, 1985;Seyfarth & Barth, 1972;Seyfarth, Hargenvioder, Ebbes, & Barth, 1982). ldiothetic cues are also used by night-active rodents, which integrate internal vestibular changes to compute their position modifications (Seguinot, Maurer, & Etienne, 1993).…”