Focals and Scans

A Very Handsome Mole Rat

There are two main types of observations we do on the mole rats to collect behavioral data. The more common type is focal scans. For a focal, we follow the activity period of a single animal, ideally from the time they leave the nest to when they go back in. Luckily with mole rats, they are generally only active for an hour or so at a time on average. There are of course some outliers, like super pregnant females or young pups that only come out for maybe ten minutes, and the really hard workers that will be going for over two hours.

Starting the focal can sometimes take the most time. Right now we have to wait and watch a colony for the animal to come out, which can take a couple hours. There is however a device that is in the early stages of implementation, that will allow us to have an alarm go off when a particular animal leaves the nest. The device reads the implanted chips inside the mole rats which have individual numbers, basically the same thing that dogs and cats get.

Sometimes the animal is already active when we enter a room, and they we do an ‘incomplete’ focal, which just means that it does not cover an entire activity period since we don’t know how long they’ve been active. The best type for data though is the complete focal.

The other type of observation we do is a scanning observation. We do twelve hours scans of specific colonies a couple times a week. The twelve hours is split into four shifts, and generally two people split up the shifts. We try to start the scan right at seven in the morning, so we aren’t working too late.

For this type of observation, we are collecting data on all the individuals in the colony. We have a special program on tablets that we carry when doing the scans and focals. The program lets us record the behaviors of each animal. For the twelve hour scan, we record what each individual is doing every four minutes. In total, it is 180 scans done during the observation period. Amazingly, four minutes is generally more than enough time to find each one, and the rest of each period is used for continuous sampling.

What this means is that once we have recorded a behavior for each animal in the colony (including rest if it is not visible), then we watch and record any social behaviors in the remaining time. Some examples of social behaviors we record include sniffing, biting, pull-tail, and pup carry. We also include certain vocalizations and mating behaviors.

When the colony is active, the time passes by very quickly. Each four minute scan is filled with observations and there is plenty to watch. The worst part is when there’s only one or two animals awake. It can be difficult to find something to occupy the mind when trapped in a room surrounded by mole rats, watching time tick slowly by on the tablet. The four minute period can suddenly feel like forever, when you have one animal that’s eating, the rest are sleeping, and no social behaviors are happening.

The twelve hour scan days do lead to a great feeling of accomplishment though, especially when working the last shift. Also, it really helps you get acquainted with a colony, and certain individuals start to stand out. If you ask me right now, I would much prefer to focal Curie or G10 over G4 or Mandela. It feels wrong, but I can’t help but have some preferences for certain colonies.

Anyway, our weeks involve many focals and some scans, as well as other specific experiments, sample collection, and data entry. There’s also always stuff to clean, and things to prepare for the next day. I’m definitely not bored here, that’s for sure!