Elephant seal tears

Last week during my volunteer shift at Marine Mammal Center I was checking on all the animals before preparing for the first feed and I came upon a sleeping Northern Elephant Seal named Annabellini.  I lingered awhile waiting for him to breathe so I knew he was okay, but I guess I disturbed him somehow.  He stirred a little, moved a flipper and then opened his eyes.  And that's when it happened:  Two streams of water, one from each eye, shot out about 18 inches each -as if they came from a fat, hairy, double-barrelled squirt gun!  A new volunteer was with me and said "Wow!  What just happened?".  In my (almost) year of experience I had never seen anything like that before, so I just said "Well, I guess he's well hydrated!".

After we finished feeding the animals on site I asked some fellow volunteers about what I had seen and in their (up to 20 years') experience none of them had ever seen an elephant seal shoot water from it's eyes.  As we talked, Dr Lorraine passed by and she had no explanation either.  At this point I started to feel a little silly and began doubting what I saw.  But, Dr Francis Gulland came by later, so I explained what I saw one more time and asked if she had any idea what had happened.  Of course she did.  Seals lack nasolachrymal ducts!  -I passively knew this, but not how it related to what I saw.  Before I explain it any further, let me back up:

Anyone who has observed seals knows that when they are dry they often have a ring of wetness around their eyes.  It is part of what makes them so cute -it often looks like they were crying.  At Marine Mammal Center we recognize this as a sign of good hydration, but why do the tears spill out of the eyes in seals? 

Most land mammals produce tears constantly, but the excess tears drain through a duct in the corner of the eye called the nasolacrymal duct which drains into the nose.  This is why a person tends to get a runny nose when they cry!  But, seals lack that duct so their tears just seep from their eyes constantly.  (This is probably because they spend most of their time in the ocean where the draining of tears is not important.)

Here's a diagram of tear production in humans which is the same for most land mammals:


So, back to the dramatic event of an elephant seal shooting water from its eyes:  Dr Gulland said that this was a sign that the seal was severely DEhydrated!  She said that in his sleep, due to a decrease in tears, his eyelids likely sealed shut.  The slow production of tears allowed the fluid to build up behind the eyelids.  When I disturbed him and he opened his eyes the pressure was released causing the fluid to shoot out.

How cool is that?

Comparing dog food prices

I just ran out of dog food and, once again, decided to re-evaluate the dog food I'm feeding since my budget is shrinking by quite a bit.  I had been feeding Taste of the Wild, but wondered if another brand would be less expensive.  Last week I went to check out prices for Purina Pro Plan or Purina One, but I was surprised to find out that on a price per pound basis they were about the same.  Then I got to thinking this morning and remembered that when I had been feeding Purina One before I had to give much more per meal which meant I ran out faster.  I wondered how to compare food pricing more accurately and came up with this (below).  Yes it is math, no it's not hard, and I will I walk you through it and then provide a fool-proof worksheet in case you want to gather information and compare dog food prices yourself.

Let's say you have your choices narrowed down to 2:

Brand A's dog food is $35 for a 30lb bag.
Brand B's dog food is $45 for a 35lb bag.

You can determine price per pound by dividing the price by the number of pounds like this:

Brand A's cost per pound is:  $35/30lbs = $1.17/lb
Brand B's cost per pound is:  $45/35lbs = $1.29/lb

(And if you are like me and forget which number to divide by the other, just remember "price per pound" because that's the order you punch them in PRICE <divided by> # OF POUNDS.  Easy!)

So, it seems at first glance that Brand A is the better deal.  But, like I said before there is another tricky factor that most consumers don't think about and that is the recommended amount to feed your dog.  Often high quality dog foods require you to feed your dog fewer cups of food because the ingredients are absorbed better (which also leads to less to clean up after the meal, if you know what I mean). 

Unfortunately, dog food manufacturer's don't have to list the weight of their food by cup or the number of cups in the bag, so there is no precise way to calculate the number of feedings you'll get from a bag.  But, I weighed a cup of Beneful weight management and it was 3oz.  A cup of Chicken Soup Large Breed Adult food was 4oz per cup.  So, I'm going to use 3.5oz per cup which means that 1lb = 4.6 cups.  (And if you wonder how I got that: 16 ounces per pound divided by 3.5oz per cup = 3.5oz per cup.)

Brand A recommends 4 cups a day for your dog's body weight.
Brand B recommends 3 cups a day for your dog's body weight.

So, the cost of Brand A per day is:
4c per day / 4.6c per pound = 0.89lbs per day
0.89lbs * $1.17/lb = $1.04 per day to feed your dog this food.

And the cost of Brand B per day is:
3c per day / 4.6c per pound = 0.65lbs per day
0.65lbs * $1.29/lb = $0.84 per day to feed your dog this food.

So, despite our initial impression, Brand B is actually cheaper to feed than Brand A because, while the price is higher per pound, you don't have to feed as much of it.



Here's a worksheet to do this calculation yourself:

_______ price of food 

DIVIDED BY:  

_______ pounds per bag

EQUALS:

_______ price per pound

NEXT:

_______ number of cups per day to feed

DIVIDED BY:

4.6 cups per pound

OR weigh the food and divide 16oz by the number of ounces in a cup of the food to get actual cups per pound

EQUALS:

_______ number of pounds per day

NEXT:

_______ number of pounds per day (from above)

MULTIPLIED BY:

_______ price per pound (from above)

EQUALS:

_______ cost per day to feed that food