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Objective: The knowledge of an animal's age is important for disease probability, prognoses, or epidemiological questions, but unfortunately, it is often unknown for dogs in animal shelters. A simple estimating procedure is preferable being quick and easy to perform, even for non-veterinarians., Material and Methods: In 295 dogs the dimension of light reflection (diameter in millimetres), visible on the posterior lens capsule using a penlight, the grade of dental abrasion and dental tartar were documented photographically and the exact weight and age in days were obtained. These photographs were evaluated blinded. The dogs were divided randomly into two groups. The first group was used to establish a model for age determination using linear and logistic regression models considering the documented parameters, which was then validated with the data of the second group., Results: The size of ocular light reflection and age correlated significantly (r = 0.781; p < 0.001; sy,x = 2.45 years [SD of y for given x]). The linear regression model gave the final equation: Estimated age [months] = 13.954 + 33.400 × lens reflection [mm] + 8.406 × dental abrasion [grade] + 8.871 × tartar [grade] with a standard error of estimation of 2.26 years., Conclusion and Clinical Relevance: Age determination, even based on three parameters results in a large standard deviation making age estimation in dogs very crude.

The accuracy of ageing horses by their dentition was assessed by comparing the dental features with the known dates of birth of 212 trotter horses and 189 Belgian draft horses. The horses ranged in age from two to 25 years. In both breeds it was observed that the shedding of the incisors and the appearance of the dental stars were the most reliable features for age determination. In young animals, the dental configuration was similar in both breeds. With increasing age the incisor teeth of draft horses were more liable to abrasion than those of trotter horses. The sequential changes in appearance of the permanent incisors occurred earlier in draft horses than in trotters.

Criteria for estimating the age of baboons using dental characteristics have been developed and tested. These criteria used eruption, wear, and color of the premolars and molars to characterize the ages of baboons in the range of 4--11 years of age. Ages greater than 11 were grouped into a single category. Using the criteria, three judges estimated independently the ages of 49 baboons, of known and unknown ages and of both sexes, with good agreement and precision. The rank order of the estimated ages was similar to the rank order of true ages for colony born animals.

Twelve sets of incisors of Cape mountain zebras, 9 of which were from known-age individuals ranging in age from 11 months to 19 years, from the Mountain Zebra National Park, are described and depicted to illustrate not only the eruption and replacement sequence, but also the changes with increasing age in the configuration of the occlusal surfaces and of the infudibulum. Infundibula persist in maxillary incisors longer than in mandibular incisors. Shallow infundibula were still present in the maxillary incisors of a 19-year-old mare at least 4 years later than in plains zebras, E. burchelli, from the Kruger National Park. The physiological life span of Cape mountain zebras appears to be at least 26 years.