Garters in the wild react much the same as a Ribbon Snake when retreating/ alarmed. They will swim on the waters surface until there is cover on the waters edge to retreat into.
Sid
9.14 T. s sirtalis, 2.2. T. ordinoides, 1.1 T. e vagrans, 1.1 T. s parietalis,
1.0 T. s sackenii- Peninsular Ribbon