We Use MarCell Wireless Freezer Monitors on Our Mountain Lion Bait & Sample Freezers
Before using MarCell Pro Freeze Alarm wireless freezer monitors, the UC Davis Wildlife Health Center Carnivores Program lost hundreds of irreplaceable mountain lion DNA samples and multiple freezers full of mountain lion bait. Don’t even get me started on the mess and the smell.
If you plan to purchase a wireless freezer monitor or any MarCell product, code WildlifeDetections25 will save you $25. Several MarCell products are also available on Amazon.
Before MarCell Wireless Freezer Monitors Were Available
Although generally marketed for household use, vacation homes, restaurants, and other commercial settings, we rely on MarCell Profreeze Alarm wireless freezer monitors to alert us to power outages and temperature fluctuations on our remotely located mountain lion sample and bait freezers.
When I started working for the UC Davis Carnivores Program, we had four chest freezers. Two were located at the UC Agriculture and Natural Resources South Coast Research and Extension Center in Irvine, California, or “the Farm,” as it is often called. The other two were located at remote sites to help facilitate our mountain lion capture and collaring efforts in the Santa Ana Mountains and out towards Anza-Borrego State Park.
On my first day at the Farm, my supervisor, long-time colleague, and mentor, Dr. Winston Vickers, conveyed the importance of checking on the bait and sample freezers first thing each morning. He described an incident in which a tripped breaker went unnoticed, and decades worth of mountain lion, island fox, and various other wildlife DNA samples thawed and remained at room temperature for an unknown amount of time.
Thankfully, samples from most of the animals had already been sent to various labs. However, the thawing, warming, and refreezing of the remaining samples could compromise their use in future analysis.
Wireless freezer monitors were not yet available, so we relied on manual checks by staff and other facility users. The problem was that there were extended periods when no one was around.
Mountain Lion Bait Collection and Storage

In 2022, the Carnivores Program expanded its mountain lion research into the Tehachapi Mountain Range, north of Los Angeles, and the northern Gabilan and Diablo ranges, east of the Santa Cruz Mountains. Wildlife biologist Juan Gonzalez leads the Tehachapi Mountain Lion Project and the Northern California Wolf Project, and I lead the mountain lion field efforts in the Gabilans and Diablo (Pacheco Pass) areas.
Shortly after initiating these additional projects, we secured locations to place chest freezers and began collecting bait. Three of the four chest freezers we use for the Pacheco and Gabilan mountain lion projects reside in sheds on unoccupied ranches, and one was placed inside a shipping container with an extension cord running to a nearby power pole.
In all instances, no one was around to check on the freezers routinely, and the power supply at each site was highly unreliable.

What’s That Smell?
A particularly memorable lesson occurred when we placed too many carcasses in a freezer. Although they all initially fit, the freezer was unable to lower the carcasses’ temperatures fast enough to prevent them from expanding and lifting the lid.
A few days later, we received a call from the partner agency that owned the property where two of our freezers were housed. They had noticed an unpleasant smell emanating from the shed and suspected something was amiss.
We immediately responded and arrived to find a freezer full of rotting, bulging carcasses, and a swarm of flies almost too thick to see through.
How MarCell Wireless Freezer Monitors Work
We have since installed MarCell wireless freezer monitors on all of our project freezers and receive alerts via email and text whenever there are power outages or instances in which temperatures drift outside the custom range. The units also alert us when power is restored or temperatures return to normal, and we can check the status of each freezer at any time through the MarCell website or app.
Full or nearly full freezers can maintain temperatures below freezing for several hours during power outages, which are often only temporary. Therefore, I don’t rush out to the sites until the temperatures fall below a certain point for an extended period.
Since installing these wireless freezer monitors, we have successfully responded to several tripped breakers, extended power outages, and an instance in which cattle unplugged an extension cord. In each case, we were able to restore power or salvage the bait immediately.
These units have paid for themselves many times over by eliminating the need to make routine trips to each site to check on the freezers.
As mentioned previously, the MarCell Pro Freeze Alarm can be purchased directly from the MarCell website, and the code WildlifeDetections25 will save you $25 on your order. You can also buy the units on Amazon. In either instance, a monthly cell charge is also required.
MarCell Customer Service Has Been Stellar
As with most electronics, there have been a few issues. In one instance, water entered the outdoor container in which we had placed one of the units. In another, a unit owned by the Santa Clara Valley Habitat Agency malfunctioned. In each case, MarCell’s customer service immediately responded to our emails and provided detailed procedures for resetting the units. When that didn’t work, they promptly replaced the units at no additional charge.
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