This beetle was brought out by the rather warm temperatures (almost 20 °C/68 °F) we had back on 28 December (last year). Now, what's wrong with the last sentence? The temperature can be low or high, but there is no such thing as a warm, hot or cold temperature. Temperature is a measure of the average kinetic energy of the molecules making up the air or any other substance and so it can't be associated with a feeling such as warmth or cold.
After that digression, we return to the beetle in the photo, which has been identified by the good folks at BugGuide.net as Geotrupes splendidus, a dung beetle. In The Common Insects of North America, Swan and Papp (1972) write:
It constructs brood cells of cow dung; in the Southeast egg laying takes place in January, pupation in May.There were no cows where I found this individual. It obviously uses the dung of other animals and appears to be active on warm days during the winter even in Maryland.