Lambs and sheep are exactly the same animal at different life stages. A lamb is essentially a baby sheep. Across all ages of sheep, males are called rams and females are called ewes, and collectively they are known as a flock. It is common for lambs to be born individually or as twins, while triplets are less common and more are much rarer.
In this post, we break down some of the differences that distinguish a lamb from an adult sheep and features that are present in both stages of life.
Lamb Vs Sheep – Size
As a lamb is a baby sheep, there is an obvious difference in size. At birth, a lamb will weigh roughly 5 to 10 lbs (2.2-4.5 kg) but this does vary across the different sheep breeds, with some larger breeds weighing up to 12 lbs (5.4 kg). Single births will tend to be larger than those born as twins or more.
According to one body weight research project at birth, a lamb will average around 27 cm long and 35 cm tall, with variations for multiple lamb births, and across the sexes (males slightly larger). They will also grow by about 0.24 cm and 0.18 kg per day until weaned.
Adult sheep have a greater difference in weight between the sexes. Male rams weight between 100 and 350 lbs (45-160 kg), whereas female ewes average a weight between 100 and 220 lbs (45-100 kg). This varies across breeds, and across wild and type of domestic livestock (dairy, wool, meat). The average adult sheep has a shoulder height of 36 inches (91 cm) and a length of 50 inches (127 cm) but again, this differs across breeds and the gender.
Rams tend to be stockier than ewes.
Lamb Vs Sheep – Appearance
- Coat – Soft, short and delicate coat of wool. A lambs coat is usually lighter in color.
- Horns – None, though baby rams of some breeds may have stumps where horns will later grow.
- Teeth – Lambs have milk teeth that grow in over the first few weeks after birth. These start to be replaced by permanent teeth once they reach maturity.
- Build – Slender
- Coat – Long, thick coat until sheared. Much less delicate. Usually a slightly darker off-white, or cream coat.
- Horns – With some breeds, both rams and ewes grow horns, with others only rams grow horns. Then there are some that don’t grow any horns at all.
- Teeth – Adult sheep have a full set of 32 teeth.
- Build – Stocky, more so with males than females.
Lamb Vs Sheep – Diet
Lambs, for the first few weeks of their life survive from only their mothers milk. Some can be introduced to hay in their diet as early as two weeks, but it is generally at four to six weeks when they will start to significantly subsidise their diet with the same solid food as adult sheep. They will continue to consume their mothers milk until around 5 to 6 months when fully weaned.
An adult sheep is herbivorous, and their diet differs depending on the nature of their home. As livestock, they may be fed a mixture of pelleted food and hay. In wilder environments or pastures they will graze heavily on grass, flowers and weeds.
Lamb Vs Sheep – Behaviour
Lambs will stick close to their mothers and their siblings. Even within a larger flock they will stay close to home. If they wander too far and out of their mothers eye, they may encounter dangers. If they mistake another sheep as their mother they can be met with hostility, and if they are at the fringes of a field they may fall foul to a predator.
Adult sheep are happy to roam a field spaced out from other members of the flock, but they are undoubtedly flock animals. Wild sheep, or those in remote holdings are happy to be solitary, but domesticated sheep don’t do well on their own and need the social connection to other sheep. They will often move, eat and sleep together. They are quite wary of strangers until they become familiar, with a strong fight or flight response.
Lamb Vs Sheep – Dangers
Pregnancy – Both lambs and their mothers can face significant risks during childbirth. There is a correlation between birth weight and survival, with medium weight being the most likely to survive. Lambs that are large in the womb have lower rates of survival, and can cause vaginal prolapse in the mother ewe.
Predation – Sheep are a prey animal for many predators including most canids (wolves, foxes, coyotes and dogs), bears, lions and even eagles. There are abundant predators because sheep have very little means to defend themselves. A flock is more likely to run than fight. It is a common behaviour of predators to go after lame, weak or young animals. So while all are vulnerable, lambs are more at risk.
When Does A Lamb Become A Sheep?
A lamb usually hits adulthood at around one year, but become independent at about 5 months and are often considered fully grown at about 6 months. At this time it will lose many of the characteristics that set it apart as a youngster, and become much more recognisable as an adult sheep.
One of the indicators that a lamb has matured into a sheep is with its teeth. When born, a lamb will start to develop milk teeth, and at around one year old, some of these – the temporary incisor teeth will start to be replaced by permanent incisors. The first two – central incisors, grow in between 12 – 19 months. They replace milk teeth in pairs, and all 8 are usually grown in by 24 – 48 months.