Ruminants have a large compound stomach. These are the mammals that chew the cud. Which of the following Ruminant lacks omasum (psalterium) chamber ?

Question

Accepted Answer

The correct option is 3: Camel
The Camel (Camelus dromedarius or Camelus bactrianus) is correctly identified as the ruminant in this list that lacks a true omasum chamber, setting it apart from the others. Camels belong to the suborder Tylopoda, which are often termed **pseudoruminants**, distinguishing them phylogenetically and anatomically from true ruminants (Ruminantia). While they share the complex, multi-stage digestive process of rumination—the chewing of cud—their stomach is composed of only three main compartments: the rumen (C1), the reticulum (C2), and the abomasum (C3, the true glandular stomach). The anatomical feature known as the **omasum** (or psalterium), which in true ruminants is a large, lamellated organ responsible for significant water and volatile fatty acid absorption, is either entirely absent or reduced to a non-functional, vestigial state in the camel. This unique adaptation, particularly the presence of glandular 'water cells' in the rumen and reticulum, allows the camel to regulate water balance with exceptional efficiency, crucial for its survival in arid environments, substituting for the typical water-absorbing role of the omasum.

The incorrect option is 1: Goat
The goat (Capra aegagrus hircus) is a member of the family Bovidae and is classified anatomically and physiologically as a **true ruminant**. True ruminants possess a fully developed, four-compartmented stomach designed for the efficient fermentation and processing of fibrous food. The goat's stomach includes the rumen, reticulum, **omasum**, and abomasum, meaning it definitely has the omasum chamber (psalterium). The omasum plays a vital role in mechanically grinding food particles and absorbing excess water and volatile fatty acids before the ingesta moves to the true stomach (abomasum). Consequently, the statement that a goat lacks an omasum is factually incorrect.

The incorrect option is 2: Sheep
The sheep (Ovis aries) is a classic example of a **true ruminant** belonging to the family Bovidae. Just like goats and cattle, sheep depend entirely on a four-compartmented stomach for their digestive process. The four essential compartments are the rumen, reticulum, **omasum**, and abomasum. Their omasum is highly muscular and responsible for the critical function of filtering large particles and salvaging water and minerals from the digesta. This chamber is essential for fine-tuning the fermentation process. Since the sheep is a conventional ruminant with a full four-chambered system, it absolutely possesses the omasum chamber.

The incorrect option is 4: Buffalo
The buffalo, including the domestic water buffalo (Bubalus bubalis), is a large member of the Bovidae family and is structurally and physiologically a **true ruminant**. Its digestive system is fully adapted for rumination, featuring the complete four-compartment stomach apparatus. This includes a well-developed rumen, reticulum, **omasum**, and abomasum, all functioning in the typical sequence of a true ruminant. The omasum in the buffalo performs its typical role of water and nutrient absorption, and particle filtering. The efficient digestion and fermentation capabilities of the buffalo, which allow it to thrive on coarse forage, are entirely dependent on the presence and function of all four chambers. Therefore, the assertion that the buffalo lacks an omasum chamber is incorrect.