Abstract: White horses frequently suffer from malign skin cancer and visual deficiencies owing to their high sensitivity to the ultraviolet solar radiation. Furthermore, in the wild, white horses suffer a larger predation risk than dark individuals because they can more easily be detected. In spite of their greater vulnerability, white horses have been highly appreciated for centuries owing to their natural rarity. Here, we show that blood-sucking tabanid flies, known to transmit disease agents to mammals, are less attracted to white than dark horses. We also demonstrate that tabanids use reflected polarized light from the coat as a signal to find a host. The attraction of tabanids to mainly black and brown fur coats is explained by positive polarotaxis. As the host's colour determines its attractiveness to tabanids, this parameter has a strong influence on the parasite load of the host. Although we have studied only the tabanid–horse interaction, our results can probably be extrapolated to other host animals of polarotactic tabanids, as the reflection–polarization characteristics of the host's body surface are physically the same, and thus not species-dependent.

Abstract: Gegenstand und Ziel: Überprüfung der Tiergerechtheit von Abrufstationen
für Kraftfutter und Heu in der Gruppenhaltung von Pferden anhand
ethologischer und physiologischer Parameter im Vergleich zu konventionellen
Fressständen. Material und Methoden: Die Verhaltensbeobachtungen
fanden in 11 bzw. 10 Offenlaufställen mit Abrufstationen
bzw. Fressständen statt. 270 Pferde wurden individuell unterschieden.
Untersuchungsparameter waren: Drohverhalten mit und ohne Verletzungsrisiko,
Meideverhalten, Verdrängung aus dem Fressstand sowie
Herzfrequenz und Integumentverletzungen. In jedem Betrieb erfolgten
kontinuierliche Direktbeobachtungen für je einen 24-Stunden-Tag (Tortenstückverfahren).
Ergebnisse: Im Wartebereich der Abrufautomaten
traten signifikant mehr Drohgesten ohne bzw. mit Verletzungsgefahr je
Pferd und Tag (8,6 bzw. 3,0) auf als im Wartebereich der Fressstände
(3,4 bzw. 0,9). Demgegenüber konnten die Pferde in Abrufstationen
(1,4 Drohgesten je Pferd und Tag) ungestörter fressen als in Fressständen
(3,2 Drohgesten je Pferd und Tag). Insgesamt betrachtet ergab sich
jedoch bei beiden Fütterungssystemen eine geringe Anzahl an sozionegativen
Interaktionen im Bereich der Futtereinrichtungen. Die Herzfrequenz
lag im Warteareal im Durchschnitt im physiologischen Bereich
(44,59 ± 11,73 Schläge/min). Integumentverletzungen im Zusammenhang
mit dem Fütterungssystem traten nicht auf. Der wichtigste Einflussfaktor
auf die Untersuchungskriterien war der Betrieb (Fläche, Konzeption,
Management). Schlussfolgerung: Unter dem Aspekt der Tiergerechtheit
hinsichtlich des Stress- und Verletzungsrisikos durch soziale
Interaktionen eignen sich bei ordnungsgemäßer Gruppenhaltung mit
fachgerechtem Management sowohl Fressstände als auch Abrufstationen
für Pferde im Offenlaufstall.
[Objective: A comparison with regard to animal welfare of feeding
stalls and automatic feeding systems for hay and concentrates in group
housing systems for horses using parameters of ethology and physiology.
Material and method: The observations of animal behaviour took
place in 10 stables with feeding stalls and in 11 stables with automatic
feeding systems. The field around the feeding systems was divided into
three areas with comparable dimensions (waiting area, exit area and
inside of the feeding system). 270 horses were individually observed.
Parameters of research comprised: threatening behaviour with and
without risk of injury, avoiding behaviour, ”chasing away from the feeding
place”, as well as heart rate and injuries of the integument. Every
group of horses was continuously observed for 24 hours. This observation
took place on four different days and comprised six sessions, each
of 4 hours. Results: In the waiting area of the automatic systems there
were significantly more threatening gestures with and without risk of
injuries for each horse and day (8.6 and 3.0, respectively) than in the
waiting area of the feeding stalls. In contrast, the horses could eat more
relaxed in the automatic systems (1.4 threatening gestures for each
horse and day) than in the feeding stalls (3.2 threatening gestures for
each horse and day). All together the number of negative interactions in
the feeding area of both feeding systems was relatively low. The heart
rate was within the physiological range (44,59 ± 11,73 beats/min) in
the waiting area. There were no injuries of the integument in correlation
with the feeding systems. The most important factor of the observation
criteria was the individual group housing system with its different dimension,
conception and management. Conclusion: Under the aspect
of animal welfare both feeding systems are suitable for horses with respect
to the risk of stress and injuries by social interactions and under
the condition of proper group housing with professional management.]

Abstract: Despite numerous attempts to define animal tool use over the past four decades, the definition remains elusive and the behaviour classification somewhat subjective. Here, we provide a brief review of the definitions of animal tool use and show how those definitions have been modified over time. While some aspects have remained constant (i.e., the distinction between 'true' and 'borderline' tool use), others have been added (i.e., the distinction between 'dynamic' and 'static' behaviours). We present an updated, comprehensive catalog of documented animal tool use that indicates whether the behaviours observed included any 'true' tool use, whether the observations were limited to captive animals, whether tool manufacture has been observed, and whether the observed tool use was limited to only one individual and, thus, 'anecdotal' (i.e., N = 1). Such a catalog has not been attempted since Beck (1980). In addition to being a useful reference for behaviourists, this catalog demonstrates broad tool use and manufacture trends that may be of interest to phylogenists, evolutionary ecologists, and cognitive evolutionists. Tool use and tool manufacture are shown to be widespread across three phyla and seven classes of the animal kingdom. Moreover, there is complete overlap between the Aves and Mammalia orders in terms of the tool use categories (e.g., food extraction, food capture, agonism) arguing against any special abilities of mammals. The majority of tool users, almost 85% of the entries, use tools in only one of the tool use categories. Only members of the Passeriformes and Primates orders have been observed to use tools in four or more of the ten categories. Thus, observed tool use by some members of these two orders (e.g., Corvus, Papio) is qualitatively different from that of all other animal taxa. Finally, although there are similarities between Aves and Mammalia, and Primates and Passeriformes, primate tool use is qualitatively different. Approximately 35% of the entries for this order demonstrate a breadth of tool use (i.e., three or more categories by any one species) compared to other mammals (0%), Aves (2.4%), and the Passeriformes (3.1%). This greater breadth in tool use by some organisms may involve phylogenetic or cognitive differences � or may simply reflect differences in length and intensity of observations. The impact that tool usage may have had on groups' respective ecological niches and, through niche-construction, on their respective evolutionary trajectories remains a subject for future study.