There’s no doubt that this internship is one of the coolest you can have if you are interested in pandas. Getting to observe pandas all day and see inside their lives during the busy breeding season is quite an ideal gig, at least to me. Although our job is awesome there are certainly less glamorous parts to it. For example, standing nearly still in the cold for up to over an hour and a half and then going to collect fecal samples from bears all over the base. 

Hope showing off her “poop wrangling” skills

As someone who has a dog at home I have to clean up after, I personally don’t mind picking up after the bears. Especially considering it’s for science! For those who are less than jazzed about the idea, I assure you we do it for a good reason. In order to see if the males testosterone levels go up during the breeding season, and in turn affect their reproductive success, we collect fecal samples for the better part of every year. From around the beginning of August to the end of the breeding season at the end of March, fecal samples are collected every other day from male bears. 

The “loot”!

Once the samples are collected, they go into a freezer to be stored in -20 degrees Fahrenheit until they are ready to be prepared for freeze drying. When it’s time to start the process, 14 fecal samples are pulled out of the freezer and smashed. Using a rubber mallet, the original samples are reduced to smaller chunks that will be easier to process in the freeze dryer. After our Biobase Freeze Dryer is all warmed up and ready to go at -70 degrees Fahrenheit, we place the 14 smashed samples (in their individual bags) on a two-tiered tray and set them inside the cold trap of the freeze dryer to be flash frozen for three to four hours.

Smashing

I’m about as excited as someone can be when holding a bunch of poo….

When the three hours is finished, we pull the samples up, loosen up the flash-frozen chunks, place them on a tray, which suspends them above the cold trap, and place a cylindrical hood over the samples. Once the hood is lubricated and sealed tightly, the three day lyophilization process can begin. Lyophilization, also known as freeze drying, is the process of isolating a solid substance from solution by freezing the solution and evaporating the ice under the vacuum^[1]. In other words, the freeze dryer is removing all of the liquid from the samples to dry them out as much as possible. After the samples have been freeze dried for three days, or roughly 72 hours, they are ready for the last leg of their journey. 

The samples in the cylindrical hood for freeze drying

The dried samples are crushed/broken up until there is a fine powder forming in the bottom of the bag. Using stainless steel strainers, each sample is individually sifted until just the powder remains. The goal of this step is to get a few grams/vials worth of very fine fecal particles/flakes^[2]. Once the strainers are cleaned and sterilized, a metal scooper is used to  fill two 2 mL cryo-vials. Finally, after the vials are filled, the samples are logged and stored in their appropriate containers then returned to the -20 degree freezer until they are ready to be sent to Dujiangyan base for hormone testing. 

Stephanie & Gigi sifting

I hope you enjoyed a behind the scenes look at our poop-freezing process! If you have any questions let me know in the comments below!

-Haley

[1] Farlex Partner Medical Dictionary © Farlex 2012

[2] Wintle, Nate. Steps to Freeze Drying Feces. 2016.