Both the dogs and pigs have bean-shaped kidneys. But, you may easily differentiate the dog kidneys from the pig kidneys by their other external features. Here, you will know the exact answer to the question – ‘How is a dog kidney different from a pig kidney?’
Quick answer: the dog’s kidneys are bean-shaped, less elongated, and larger at the extremities than the pig’s kidneys. Kidneys of both species possess smooth surfaces, but some lobulation may be visible on the pig’s kidneys.
Here, I will discuss the typical identifying features between the kidneys of dogs and pigs with diagrams. Thus, you will easily differentiate a dog kidney from a pig kidney practically.
What are the identifying features of a dog kidney?
Both the right and left kidneys of a dog are retroperitoneal. The dorsal surface of both kidneys is in contact with the lumbar muscles and fat. Again, the ventral surface of the kidneys is covered with the transparent parietal peritoneum.
You might know the gross anatomical features to compare the kidneys between dogs and pigs. A dog’s kidney anatomy has two surfaces, borders, and extremities.
You will also find the renal hilus and other associated structures with the dog kidney. Here, I will only focus on these features essential to differentiate the dog kidneys from the pig’s kidneys.
So, let’s see the unique differentiating features of the dog kidneys –
- Both the kidneys of a dog are bean-shaped,
- The surfaces of the right and left kidneys of a dog are smooth,
- Both kidneys are thick dorso-ventrally, with a rounded ventral surface and less convex dorsal surface,
- The cranial and caudal extremities of the dog kidneys are convex and broader,
- The hilus is located in the middle of the medial border of a dog’s kidneys, and they are comparatively wide,
- Here, the longitudinal section of the dog kidney shows the renal crest and renal pelvis,
The diagram shows the external and internal gross features of the dog’s kidneys. Now, you need to know the gross anatomical features of the pig’s kidneys to compare them with the dog’s kidneys.
What are the unique identifying features of the pig kidney?
Both the right and left kidneys of a pig are also bean-shaped. They are more flattened dorsoventrally, elongated, and smaller at the extremities than the dog kidneys.
Let’s see the identifying gross anatomical features of the pig kidneys –
- The pig’s kidneys are also the bean-shaped,
- They also possess the smooth surface, sometimes some lobulation (1 – 3) may be visible on their surfaces,
- The length of the pig kidney is about twice the width,
- The cranial and caudal extremities of the pig’s kidneys are smaller and pointed,
- Both the right and left kidneys of a pig possess a narrow hilus in the middle of the medial border,
- The pelvis is funnel shape and divides into two major calyces,
Here, the diagram shows the gross anatomy of the pig kidneys. The longitudinal section of the pig kidneys also presents some variation in comparison to the dog kidneys.
How is a dog kidney different from a pig kidney?
The dog kidney differs from a pig’s kidney in its shape, size, and external features. Here, table 1 shows the difference between a dog kidney and a pig kidney –
| Kidneys and features | Dog kidneys | Pig kidneys |
| Shape of the kidneys | Bean-shaped Less elongated | Bean-shaped More elongated |
| The surface of the kidneys | Smooth | Smooth; Sometimes lobulation may present |
| Compression | Dorsoventrally more flattened | Dorsoventrally less flattened |
| Extremities | Larger, convex, and wider | Smaller, convex, and narrow |
| Dorsal surface | Less convex | Convex surface |
| Ventral surface | Rounded surface | Convex and wider surface |
| Renal pyramid | Simple and indistinct | Compound and distinct |
| Minor calyx | No distinct minor calyx | It has distinct minor calyx |
Again, the cranial extremity of the pig’s right kidney has no contact with the liver. At the same time, the cranial extremity of the dog’s right kidney has direct contact with the caudate lobe of the liver.
The renal veins of the dog’s right and left kidneys are paired. Again, the renal artery for the right and left kidneys of the dog may be single or paired.
Conclusion
So, a dog kidney is different from a pig kidney in their shape, surfaces, and features of the extremities. The external indistinct lobulation and internal distinct pyramid are other identifying features of a pig kidney from a dog kidney.
