There always seems to be a couple on sentry duty while the rest are eating. I found out they have two different sounds when sounding a alert. The 1st is not as loud or as shrill and all of them head to the top of their holes and they carry their food with them. The second is much louder and the shrill is sharper and when this happens all drop what they are doing and head into their holes. To get them sounding the hide alert I watched the sky and if a predator was in the air and coming towards them I focused on one of the sentry's.
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