A Vaishnava-based answer ahead…
We all know the story of Ganesha getting the elephant head. But do you know why Ganesha rides on the Mooshika Vaahana? Mooshika in Sanskrit means rat. Different Puranas narrate different stories of how Ganesha obtained Mooshika as His vaahana.
AS PER SKANDA PURANA:
As per the Skanda Purana, there was a demon by the name Gajamukhasura. This Gajamukhasura had the boon of Lord Shiva that no conventional weapon could harm him. Thus, he was causing a nuisance to the devatas, sages, and noble people in the three realms. All the devatas approached Lord Shiva for help. On the instructions of Lord Shiva, Lord Ganesha came to fight with him. But here, as Lord Ganesha was fighting with Gajamukhasura, all the conventional weapons like bhaala, shoola, sword, mace, etc. failed, as per the boon of Lord Shiva. Therefore, Ganesha took out His tusk and threw it at Gajamukhasura.
Now, this Gajamukhasura was frightened by the tusk thrown by Ganesha and assumed the form of a rat and charged towards Ganapati. Ganapati jumped and sat down on this rat. Gajamukhasura wasn’t able to bear the divine weight of Lord Ganesha and tried to come back into his original form, but couldn’t because he felt paralyzed. Therefore, his ego was shattered, and he repented for his mistakes and asked for forgiveness. Ganesha forgave Gajamukhasura and accepted him as his vaahana.
Thus, Gajamukhasura lived with Ganesha in his rat form only. Therefore, Ganesha is known as Mooshika Vaahana.
AS PER GANESHA PURANA:
This Ganesha Purana is known as one of the Upapurana, where the story is different. Here, there was a Gandharva by the name Krauncha. One day, he accidentally stepped on the foot of Sage Vaamadeva in Indra’s court. Because of that, Sage Vaamadeva cursed Krauncha to become a gigantic rat. This rat used to cause a nuisance to all. In the Ganesha Purana, it is stated that to destroy the demon named Sindhu, Ganesha incarnated as the son of Sage Parashara and Vatsala, by the name Mayureshwara.
Now, this rat, or Mooshika, was destroying Sage Parashara’s ashrama. Seeing this, child Ganesha threw His paasha (divine noose) on that rodent and subdued him, and made him His vaahana.
These incidents may have happened in different Kalpas. Therefore, there might be variations in the stories.
STORY ENDS HERE…
And one interesting part I want to tell you is another spiritual reason why Ganesha has Gajamukha and not anyone else’s head. And this should be known; that’s why I am telling this. Actually, Ganesha is the presiding deity for Aakasha Tattva. Just as Bhagavan is present in everyone, in Ganesha too, Bhagavan Vishnu is present in the form of Vishvambhara, as stated in the Maandukya Upanishad:
जागरितस्थानो बहिष्प्रज्ञः सप्ताङ्ग एकोनविंशतिमुखः स्थूलभुग्वैश्वानरः प्रथमः पादः ॥ ३॥
"The first quarter (of the Self) is Vaishvanara, whose sphere of activity is the waking state, who is conscious of external objects, who possesses seven limbs and nineteen faces, and who experiences gross material objects.”
[Maandukya Upanishad]
Here, this Vaishvaanara, who is Paramatma Himself, is known as Vishvambhara. This Vishvambhara is the form of Lord Vishnu. In this form, the central face is an elephant face, and except that, there are 18 male faces, totalling 19 faces (एकोनविंशतिमुखः). Lord Vishvambhara has a broad chest, a slender belly, and holds the vara and abhaya mudras (Vara means the Ashirvaada Mudra, and Abhaya means the inverted Ashirvaada Mudra). In the other two hands, He is holding the Shankha and Chakra. So, this is the Vishvambhara roopa of Lord Vishnu as shown below:
[Image of Lord Vishvambhara, the form of Lord Vishnu]
Lord Vishnu has 4 forms: Vishva or Vishvambhara, Taijasa, Turya, Praajna. Out of these forms, the Vishva form is the Vishvambhara roopa of Bhagavan Vishnu. Through this Vishvambhara form, He enables us to see this world and is handling the department of Jaagrata avastha, which is the awakened state. This Vishvambhara roopi Lord Vishnu is the one who is present within Lord Ganesha, and with the grace of this Vishvambhara roopi Paramatma, Ganesha does Vighnanivaarana and is known as Vighneshwara or VighnaVinayaka or Vighnaharta and is worshipped first during any satkaarya. There is even an idiom named ‘Sri Ganesh karna’. That’s why the first name in the Vishnu Sahasranaama is Vishva. Vishva roopi Paramatma makes Ganapati remove all our obstacles and is the Prathama Poojya, and due to His grace, Ganapati is Prathama Poojya.
Because Ganesha constantly and intensely meditated on this form of Lord Vishvambhara, and especially the Gajamukha of Lord Vishvambhara, He got the Gajamukha, or the elephant head. It is like the way you contemplate Lord Vishnu, the way you become. For example, if you contemplate that Bhagavan is full of pure knowledge, then you will also get pure knowledge, but as per your competence. Like that only, Ganesha contemplated the Gajamukha of Lord Vishvambhara; that’s why He got the Gajamukha, as we hear in the stories told in the Skanda Purana and the Brahmavaivarta Purana.
May Lord Ganesha, who is Vighnahara, remove all our obstacles and help us reach our dreams and goals, and give us devotion, knowledge, intellect, and a lot of abundance in our lives! 🙏🌸✨😊 Please comment on how you like my answer, because your comment matters!😊
Hope this helps!
Jay SriRam!
Ganapati Bappa Morya!😊🙏
Mangal Moorti Morya!🌸✨
ShriGanapati Antargata ShriBhaaratiRamana Mukhyaprana Antargata SriVishvambhara Abhinna SriKrishnarpanmastu!