Freezing Specimens And How To Mitigate Freezer Burn.

Written by Jazmine Miles Long, Taxidermist. https://www.jazminemileslong.com, Twitter: @TaxidermyLondon; Instagram: @Jazmine_miles_long

In my opinion there isn’t one system to do things correctly in taxidermy, every museum or taxidermist may have their own preferences and strategies already in place. This is simply a guideline that works for me, and I hope it can help others to mitigate some of the problems I encounter when working with skins that have been frozen in a way that has accelerated freezer burn. Following this advice might get more time out of frozen specimens and give you a greater chance that they can be mounted once the budget or staff time is there to pay for taxidermy or processing cabinet skins.

What is freezer burn?

Freezer burn happens when the moisture is evaporated out of the animal’s skin and muscles over time in the freezer. Most specimens even if they are well packed in the freezer will still get some freezer burn over a long period of time but it will be much worse if the specimen is poorly packaged or has something absorbent (like a paper label) inside the bag with it.

You can tell if a specimen has freezer burn because it will look white and dry in areas such as the feet, hands, around the eyes, ears, and mouth. And when you start skinning the skin will be yellowed and hard to remove rather than red, fleshy, and easy to peel away.

Firstly, I advise to always freeze your specimens before handling or skinning them. At a minimum you could record the specimen’s weight before freezing as this measurement is affected slightly after freezing. I personally would not take any other measurements until after they have been thoroughly frozen (unless you want to collect live parasites). As the animal dies, any parasites on the skin of the animal will leave the body as it cools and hop onto the next willing subject which will be you or any living creature in your lab! A note that fleas are not killed over night, if you freeze a fox for example leave it in there for at least two weeks before defrosting. It completely depends on the temperature of your freezer however so if you start to defrost an animal the fleas will defrost first, so if there is movement you know to refreeze! Obviously very large animals may need to be skinned straight away, so in this case my advice is wear appropriate PPE.

Great Spotted woodpecker. Image by Jazmine Miles Long.
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NatSCA Digital Digest

Welcome to the weekly digest of posts from around the web with relevance to natural science collections. We hope you find this useful and if you have any articles that you feel would be of interest, please contact us at blog@natsca.org

1. Blog: A Day Out at Tring

Amy Freeborn, Natural History Museum London

Synopsis

This blog covers some of the history of the collections at Tring, and includes some interesting historical photos of the Museum and Rothschild’s estate as it was in the early 1900s. The author had the opportunity to see the preparation lab where beetles are used to clean flesh from carcasses, leaving skeletons fit for mounting. Some ‘wow-factor’ facts regarding the content of Tring Museum’s collections are also outlined.

http://www.nhm.ac.uk/natureplus/blogs/behind-the-scenes/2014/03/14/a-day-out-at-tring

The galleries at Tring Museum. Image by Robert Stainforth. Obtained from http://www.commons.wikimedia.org

2. Blog: Testing a European Competency Framework for VET in Collections Management

National Agency for Lifelong Learning

Synopsis

Access to, and use of, natural history collections are integral in facilitating research in the sector, but the ways in which these are facilitated vary between institutions. This article looks at the application of ‘best practice’ in terms of collections management, care, and conservation and describes a project that utilises the methods developed by the Natural History Museum, London to tackle the task of creating a standard for European collections.

http://www.adam-europe.eu/adam/project/view.htm?prj=10833&projLang=en#.UvpDWvtWsfg

3. Training: Pest Identification and Trapping Study Day

The Horniman Museum, London. 15th May 2014

Synopsis

An introduction to the management of museum pests. The day comprises lectures on subjects such as Integrated Pest Management schemes, as well as practical sessions that will give attendees the skills to identify various pest species. The Horniman Museum is used as a case study to illustrate an active pest management scheme. The highlight (having attended myself previously) is a pest based treasure hunt in the natural history galleries.

There is a limited number of places on this course so please get in touch with Libby Finney for details asap if you are interested. Email: lfinney@museumoflondon.org.uk

A horde of Anthrenus larvae on a bird skull. (C) UCL Grant Museum

4. Event: Geological Carbon Storage: Meeting the Global Challenge

Two day conference at the Geological Society at Burlington House. 14th-15th April 2014

Synopsis

Fossil fuels will undeniably be a significant component of energy supplies for ‘several decades at least’. This conference will focus on actions required to avoid serious negative environmental impacts caused by the burning of fossil fuels and the subsequent amount of CO2 that is released. Trapping CO2 and storing it underground (CCS) is a method of achieving this aim. Issues and policies will be discussed by delegates including members of government, industry, regulators and NGOs.

http://www.geolsoc.org.uk/carbonstorage14

Compiled by Emma-Louise Nicholls, NatSCA Blog Editor