Animals which are considered too slow-moving to be 'free' are not included in this category, as trapping them does not change their legal status of being able to grab them in 'one hand swoop' (a term used by the Rambam to define this law). A snail, tortoise, etc. may therefore be confined as they can be grabbed just as easily whether they are in an enclosure or unhindered in the wild. For these purposes trapping them serves no change to their legal status regarding their 'ease of capture,' and they are termed legally pre-trapped due to their nature. Trapping is therefore seen not as a 'removal of liberty,' which caging even such a slow moving creature would be, but rather the confining of a creature to make it easier to capture in one's hand.