Ah, the yearly dilemma of figuring out whether a Soay lamb is light phase. We Soay breeders never seem to tire of talking and fussing about it, do we? At least I don’t. I have written about it several times right here, and people tell me they find one of those posts particularly useful in analyzing their lambs. Time for an update.
Earlier this week Steve and I were working a pair of newborns from our light phase ewe, Dora. Usually we focus on just one lamb, or we try to compare lambs from two different sets of parents born on different days or photographs taken under varying light conditions. But this time we took advantage of the opportunity to eliminate all variables except the phenotype itself: the twins obviously are from the same parents, born at the same time, and photographed simultaneously. We hope this set of photos will help those of you who are trying to decipher the phenotypes of your own lambs.
The twins are both ewes. Both have lightly frosted fleece, white splotches on their heads, and cute little dark noses (about those noses, see the mea culpa at the end of this post). One lamb’s legs are slightly darker, at least to my eye. I took this first photo in the working area of the Maternity Ward in mid-afternoon in natural sunlight.
Dora's twin ewe lambs age 2 days
The next picture, taken from a different angle, begins to reveal subtle differences in the colors of the twins’ noses, legs, and so forth, but still not much clue about a possible light phase lamb or two, is there?
Soay twins exploring with mom
When we began working these lambs, we were struck by how much they looked alike. It was not until we paused the working ritual to run through the list of clues for light phase that we knew we had one light phase lamb. As you may recall if you’re a student of Soay phenotypes, sometimes but not always the light phase sheep have pale skin under their tails. That didn’t help in this case. Usually, but not always, light phase lambs have somewhat paler skin around their lips and light noses, and we saw some variation between the two lambs, but not enough to rely on. Two characteristics, however, are always reliable indicators and they worked just as predicted on the twins: eye margins and fleece roots. To illustrate these two telltale signs, we put together three pairs of photos taken the day they were born – first showing each lamb’s eye margins, next showing their eye margins up real close, and last showing their fleece roots. These photos were taken in a jug with a roof, so we needed to use shop lights, but no flash.
First up, eye margins:
Dora's tan ewe lamb
Dora's dark phase lamb
Even though the lambs’ eyes look the same in the more-distant photos at the beginning of this post, up closer and placed side by side, the difference is obvious, isn’t it?
Now let’s look zero in to be sure there is enough difference to rely on.
Light phase Soay lamb
Dark phase Soay lamb
Here’s the trick about eye margins. You really have to pick up the lamb and get a good close look to be sure.
Not to worry. There is another equally reliable, and I think easier, way to tell light from dark phase – the roots of the fleece. Even a frosty, light-fleeced lamb will have black or near-black fleece roots if it is dark phase, and a light phase lamb will always have fleece roots no darker than medium brown, never black. Here are Dora’s twins with their fleece roots exposed. [Author's note: please disregard the scaggy looking fingernails and cuticles of the photographer's assistant. She's deep into lambing duty with no time for manicures].
Light phase lamb's fleece roots
Dark phase lamb's black fleece roots
A note about those dark noses. Just a few days ago I told another breeder who sent us a photo asking for help that her lamb is not light phase because in the picture it had what looks like a dark nose, not the lighter nose and lips that are typical in light phase lambs. Looking at our twins up close, the light phase lamb’s nose and lips are somewhat lighter, but by golly, when you look at these lambs from a distance, they sure look like dark noses to me. My apologies to the other breeder (you know who you are!) for questioning the phenotype of her lamb based solely on the appearance of its nose from a distance.
Enough of genetic analysis. How’s this for a sweet picture of a Soay mother and her babies? Enjoy the photo, and have fun with your phenotypic detective work!
Resting after big adventure
For now …
